Sun Microsystems System Administration Guide, Volume 1 (2000)

TABLE 32-4

The analyze Menu Item Descriptions

(continued)

The Command ... Allows You To ...

setup

Specify the following analysis parameters

Analyze entire disk? yes

Starting block number: depends on drive

Ending block number: depends on drive

Loop continuously? no

Number of passes: 2

Repair defective blocks? yes

Stop after first error? no

Use random bit patterns? no

Number of blocks per transfer: 126 (0/n/nn)

Verify media after formatting? yes

Enable extended messages? no

Restore defect list? yes

Restore disk label? yes

Defaults are shown in bold.

config

View the current analysis parameters.

quit

Exit the analyze menu.

The defect Menu

The defect menu looks like this.

format> defect

DEFECT MENU:

primary

- extract manufacturer’s defect list

grown

- extract manufacturer’s and repaired defects lists

both

- extract both primary and grown defects lists

- display working list

dump

- dump working list to file

quit

defect>

The table below describes the defect menu items.

398

TABLE 32-5

The defect Menu Item Descriptions

The Command ... Allows You To ...

primary

Read the manufacturer’s defect list from the disk drive and update the

in-memory defect list.

grown

Read the grown defect list (defects that have been detected during

analysis) and update the in-memory defect list.

both

Read both the manufacturer’s and grown defect list and update the

in-memory defect list.

View the in-memory defect list.

dump

Save the in-memory defect list to a file.

Exit the defect menu.

quit

Files Used by format (format.dat)

The format data file, /etc/format.dat, contains:

Disk types

Default slice tables

The format.dat file shipped with the Solaris operating environment supports

many standard disks. If your disk drive is not listed in the format.dat file, you can

choose to add an entry for it or allow format to prompt you for the information it

needs while it is performing operations.

Adding an entry to the format.dat file can save time if the disk drive will be used

throughout your site. To use the format.dat file on other systems, copy the file to

each system that will use the specific disk drive you added to the format.dat file.

You should modify the data file for your system if you have one of the following:

A disk that is not supported by the Solaris operating environment

A disk with a slice table that is different from the Solaris operating environment

default configuration

The format Utility (Reference)

399

Note - Do not alter default entries. If you want to alter the default entries, copy the

entry, give it a different name, and make the modification to avoid confusion.

Structure of the format.dat File

The format.dat contains specific disk drive information used by the format

utility. Three items are defined in the format.dat file:

Search paths

Disk types

Slice tables

Syntax of the format.dat File

The following syntax rules apply to the data file:

The pound sign (#) is the comment character. Any text on a line after a pound

sign is not interpreted by format.

Each definition in the format.dat file appears on a single logical line. If the

definition is more than one line long, all but the last line of the definition must

end with a backslash (\).

A definition consists of a series of assignments that have an identifier on the left

side and one or more values on the right side. The assignment operator is the

equal sign (=). The assignments within a definition must be separated by a colon

(:).

White space is ignored by format. If you want an assigned value to contain white

space, enclose the entire value in double quotes ("). This will cause the white

space within the quotes to be preserved as part of the assignment value.

Some assignments can have multiple values on the right hand side. Separate

values by a comma.

Keywords in the format.dat File

The data file contains disk definitions that are read in by format when it is started.

Each definition starts with one of the following keywords: search_path,

disk_type, and partition, which are described in the table below.

400

TABLE 32-6

format.dat Keyword Descriptions

Keyword

Use

search_path

This keyword is no longer used in the format.dat file. Starting with the Solaris 2.0

release, the format utility searchs the logical device hierarchy (/dev) so there is no need

to set this keyword to find a system’s disks.

disk_type

Defines the controller and disk model. Each disk_type definition contains information

concerning the physical geometry of the disk. The default data file contains definitions for

the controllers and disks that the Solaris operating environment supports. You need to add

a new disk_type only if you have an unsupported disk. You can add as many

disk_type definitions to the data file as you want.

partition

Defines a slice table for a specific disk type. The slice table contains the slice information,

plus a name that lets you refer to it in format. The default data file contains default slice

definitions for several kinds of disk drives. Add a slice definition if you recreated slices on

any of the disks on your system. Add as many slice definitions to the data file as you need.

Disk Type (format.dat)

disk_type defines the controller and disk model. Each disk_type definition

contains the physical geometry of the disk. The default data file contains definitions

for the controllers and disks that the Solaris operating environment supports. You

need to add a new disk_type only if you have an unsupported disk. You can add

as many disk_type definitions to the data file as you want.

The keyword itself is assigned the name of the disk type. This name appears in the

disk’s label, and is used to identify the disk type whenever format is run. Enclose

the name in double quotes to preserve any white space in the name. The table below

describes the identifiers that must also be assigned values in all disk_type

definitions.

TABLE 32-7

Required disk_type Identifiers

Identifier

Description

ctlr

Valid controller type for the disk type. Currently, the supported values

for this assignment are SCSI and ISP-80 (IPI controller).

ncyl

The number of data cylinders in the disk type. This determines how

many logical cylinders of the disk the system will be allowed to access.

The format Utility (Reference)

401

TABLE 32-7

Required disk_type Identifiers

(continued)

Identifier

Description

acyl

The number of alternate cylinders in the disk type. These cylinders are

used by format to store information such as the defect list for the drive.

You should always leave at least two cylinders for alternates.

pcyl

The number of physical cylinders in the disk type. This number is used

to calculate the boundaries of the disk media. This number is usually

equal to ncyl plus acyl.

nhead

The number of heads in the disk type. This number is used to calculate

the boundaries of the disk media.

nsect

The number of data sectors per track in the disk type. This number is

used to calculate the boundaries of the disk media. Note that this is only

the data sectors, any spares are not reflected in the assignment.

rpm

The rotations per minute of the disk type. This information is put in the

label and later used by the file system to calculate the optimal placement

of file data.

Other assignments might be necessary depending on the controller. The table below

describes the assignments required for SCSI controllers.

TABLE 32-8

disk_type Identifiers for SCSI Controllers

Identifier

Description

fmt_time

A number indicating how long it takes to format a given drive. See the

controller manual for more information.

A number that controls the operation of the onboard cache while format is

cache

operating. See the controller manual for more information.

trks_zone

A number that specified how many tracks you have per defect zone, to be

used in alternate sector mapping. See the controller manual for more

information.

asect

The number assigned to this parameter specifies how many sectors are

available for alternate mapping within a given defect zone. See the controller

manual for more information.

Below are some examples of disk_type definitions:

402

disk_type = "SUN1.3G" \

: ctlr = SCSI : fmt_time = 4 \

: trks_zone = 17 : asect = 6 : atrks = 17 \

: ncyl = 1965 : acyl = 2 : pcyl = 3500 : nhead = 17 : nsect = 80 \

: rpm = 5400 : bpt = 44823

disk_type = "SUN2.1G" \

: ctlr = SCSI : fmt_time = 4 \

: ncyl = 2733 : acyl = 2 : pcyl = 3500 : nhead = 19 : nsect = 80 \

: rpm = 5400 : bpt = 44823

disk_type = "SUN2.9G" \

: ctlr = SCSI : fmt_time = 4 \

: ncyl = 2734 : acyl = 2 : pcyl = 3500 : nhead = 21 : nsect = 99 \

: rpm = 5400

Partition or Slice Tables (format.dat)

A partition definition keyword is assigned the name of the slice table. Enclose the

name in double quotes to preserve any white space in the name. The table below

describes the identifiers that must be assigned values in all slice tables.

TABLE 32-9

Required Identifiers for Slice Tables

Identifier

Description

disk

The name of the disk_type that this slice table is defined for. This name

must appear exactly as it does in the disk_type definition.

The disk controller type this slice table can be attached to. Currently, the

ctlr

supported values for this assignment are ISP-80 for IPI controllers and SCSI

for SCSI controllers. The controller type specified here must also be defined

for the disk_type chosen above.

The other assignments in a slice definition describe the actual slice information. The

identifiers are the numbers 0 through 7. These assignments are optional. Any slice

not explicitly assigned is set to 0 length. The value of each of these assignments is a

pair of numbers separated by a comma. The first number is the starting cylinder for

the slice, and the second is the number of sectors in the slice. Below are some

examples of slice definitions:

partition = "SUN1.3G" \

: disk = "SUN1.3G" : ctlr = SCSI \

: 0 = 0, 34000 : 1 = 25, 133280 : 2 = 0, 2672400 : 6 = 123, 2505120

partition = "SUN2.1G" \

: disk = "SUN2.1G" : ctlr = SCSI \

(continued)

The format Utility (Reference)

403

(Continuation)

: 0 = 0, 62320 : 1 = 41, 197600 : 2 = 0, 4154160 : 6 = 171, 3894240

partition = "SUN2.9G" \

: disk = "SUN2.9G" : ctlr = SCSI \

: 0 = 0, 195426 : 1 = 94, 390852 : 2 = 0, 5683986 : 6 = 282, 5097708

Specifing the Location of a format Data File

The format utility learns of the location of your data file by the following methods.

1. If a filename is given with the -x command line option, that file is always used as

the data file.

2. If the -x option is not specified, then format looks in the current directory for a

file named format.dat. If the file exists, it is used as the data file.

3. If neither of these methods yields a data file, format uses /etc/format.dat as

the data file. This file is shipped with the Solaris operating environment and

should always be present.

Rules for Input to format Commands

When using the format utility, you need to provide various kinds of information.

This section describes the rules for this information. See “Using format Help” on

page 406 for information on using format’s help facility when inputting data.

Inputting Numbers to format Commands

Several places in format require an integer as input. You must either specify the

data or select one from a list of choices. In either case, the help facility causes

format to print the upper and lower limits of the integer expected. Simply enter the

number desired. The number is assumed to be in decimal format unless a base is

explicitly specified as part of the number (for example, 0x for hexadecimal).

The following are examples of integer input:

404

Enter number of passes [2]: 34

Enter number of passes [34] Oxf

Specifying Block Numbers to format Commands

Whenever you are required to specify a disk block number, there are two ways to

input the information:

Block number as an integer

Block number in the cylinder/head/sector format

You can specify the information as an integer representing the logical block number.

You can specify the integer in any base, but the default is decimal. The maximum

operator (a dollar sign, $) can also be used here to let format select the appropriate

value. Logical block format is used by the SunOS disk drivers in error messages.

The other way to specify a block number is by the cylinder/head/sector designation.

In this method, you must specify explicitly the three logical components of the block

number: the cylinder, head, and sector values. These values are still logical, but they

allow you to define regions of the disk related to the layout of the media.

If any of the cylinder/head/sector numbers are not specified, the appropriate value

is assumed to be zero. You can also use the maximum operator in place of any of the

numbers and let format select the appropriate value. Below are some examples of

cylinder, head, and sector entries:

Enter defective block number: 34/2/3

Enter defective block number: 23/1/

Enter defective block number: 457//

Enter defective block number: 12345

Enter defective block number: Oxabcd

Enter defective block number: 334/$/2

Enter defective block number: 892//$

The format utility always prints block numbers, in both of the above formats. Also,

the help facility shows you the upper and lower bounds of the block number

expected, in both formats.

Specifying format Command Names

Command names are needed as input whenever format is displaying a menu

prompt. You can abbreviate the command names, as long as what you enter is

sufficient to uniquely identify the command desired.

For example, use p to enter the partition menu from the format menu. Then

enter p to display the current slice table.

The format Utility (Reference)

405

format> p

PARTITION MENU:

- change ‘0’ partition

- change ‘1’ partition

- change ‘2’ partition

- change ‘3’ partition

- change ‘4’ partition

- change ‘5’ partition

- change ‘6’ partition

- change ‘7’ partition

select - select a predefined table

modify - modify a predefined partition table

name

- name the current table

- display the current table

label

- write partition map and label to the disk

quit

partition> p

Specifying Disk Names to format Commands

There are certain times in format when you must name something. In these cases,

you are free to specify any string you want for the name. If the name has white

space in it, the entire name must be enclosed in double quotes ("). Otherwise, only

the first word of the name is used.

Using format Help

The format utility provides a help facility you can use whenever format is

expecting input. You can request help about what information is expected by

entering a question mark (?). The format utility displays a brief description of what

type of input is needed.

If you enter a ? at a menu prompt, a list of available commands is displayed.

Associated format Man Pages

The man pages associated with the format utility is format(1M), which describes

the basic format utility capabilities and provides descriptions of all command line

variables, and format.dat(4), which describes disk drive configuration information

for the format utility.

406

CHAPTER

Managing File Systems Topics

This section provides instructions for managing file systems in the Solaris operating

environment. This section contains these chapters.

Provides a high-level overview of file system concepts,

Chapter 34

including descriptions of the types of file systems,

commonly used administration commands, and the

basics of mounting and unmounting file systems.

Provides step-by-step procedures to create a UFS file

Chapter 35

system, create and preserve a temporary file system

(TMPFS), and create a loopback file system (LOFS).

Provides step-by-step procedures to determine what file

Chapter 36

systems are mounted, how to mount files listed in the /

etc/vfstab file, and how to mount UFS, NFS, and

PCFS (DOS) file systems.

Provides overview information and step-by-step

Chapter 37

instructions for using the Cache File System (CacheFS^TM ).

Provides step-by-step procedures for configuring

Chapter 38

additional swap space, monitoring swap resources,

creating swap files and making them available, and

removing extra swap space.

407

CHAPTER

Managing File Systems (Overview)

This is a list of the overview information in this chapter.

“What’s New in File Systems?” on page 409

“Types of File Systems” on page 416

“File System Administration Commands” on page 419

“The Default Solaris File Systems” on page 421

“Swap Space” on page 422

“The UFS File System” on page 423

“Mounting and Unmounting File Systems” on page 425

“Determining a File System’s Type” on page 430

What’s New in File Systems?

This section describes new file system features.

The /var/run File System

A new TMPFS-mounted file system, /var/run, is the repository for temporary

system files that are not needed across system reboots in this Solaris release and

future releases. The /tmp directory continues to be repository for non-system

temporary files.

409

Because /var/run is mounted as a memory-based file system rather than a

disk-based file system, updates to this directory do not cause unnecessary disk traffic

that would interfere with systems running power management software.

The /var/run directory requires no administration. You may notice that it is not

unmounted with the umount -a or the umountall command.

For security reasons, /var/run is owned by root.

Mount Table Changes (/etc/mnttab)

In previous Solaris releases, /etc/mnttab was a text-based file that stored

information about mounted file systems. The downside of being a file was that it

could get out of sync with the actual state of mounted file systems.

Now the /etc/mnttab file is a MNTFS file system that provides read-only

information directly from the kernel about mounted file systems for the local system.

Note the following mnttab behavior changes:

Programs or scripts attempting to write to /etc/mnttab will fail.

The mount -m option for faking mnttab entries no longer works.

No administration is required for the /etc/mnttab mount table.

See mnttab(4) for more information.

Using the Universal Disk Format (UDF)

File System

The UDF file system, the industry-standard format for storing information on the

optical media technology called DVD (Digital Versatile Disc or Digital Video Disc), is

included in this Solaris release.

The UDF file system is provided as dynamically loadable, 32-bit and 64-bit modules,

with system administration utilities for creating, mounting, and checking the file

system on both SPARC and IA platforms. The Solaris UDF file system works with

supported ATAPI and SCSI DVD drives, CD-ROM devices, and disk and diskette

drives. In addition, the Solaris UDF file system is fully compliant with the UDF 1.50

specification.

The UDF file system support is provided in the following new packages:

SUNWudfr — 32-bit kernel component

SUNWudfrx — 64-bit kernel component

410

SUNWudf — /usr component

UDF Features and Benefits

In this Solaris release, the UDF file system provides the following features:

Ability to access the industry standard CD-ROM and DVD-ROM media when they

contain a UDF file system.

Flexibility in exchanging information across platforms and operating systems.

A mechanism for implementing new applications rich in broadcast-quality video,

high-quality sound along with the richness in interactivity using the DVD video

specification based on UDF format.

The following features are not included in this UDF file system release:

Support for write-once media, CD-RW, and DVD-RAM, with either the sequential

disk-at-once and incremental recording.

UFS components such as quotas, ACLs, transaction logging, file system locking,

and file system threads, which are not part of the UDF 1.50 specification.

Hardware and Software Requirements

The UDF file system requires the following:

The Solaris 7 11/99 or the Solaris 8 release

Supported SPARC or Intel platforms

Supported CD-ROM or DVD-ROM device

UDF Compatibility Issues

This first Solaris UDF file system implementation provides:

Support for industry-standard read-write UDF version 1.50.

Fully internationalized file system utilities.

How to Connect a DVD-ROM Device

1. Become superuser.

2. Create the /reconfigure file.

# touch /reconfigure

Managing File Systems (Overview)

411

3. Shut down the system and turn off power.

# init 0

4. Connect the DVD-ROM device.

5. Turn on power to the system.

How to Access Files on a DVD-ROM Device

1. Verify the DVD-ROM device is automatically mounted.

$ ls /cdrom

Note - If the system has both a CD-ROM and DVD-ROM device, the CD-ROM

might be named /cdrom/cdrom0 and the DVD-ROM might be named

/cdrom/cdrom1. If the system only has a DVD-ROM device, then try using

/cdrom/cdrom0.

2. Display content with ls command.

$ ls /cdrom/cdrom1

Automatic display with the CDE file manager is not implemented yet. All other

CDE file manager functions—drag and drop for copying and imagetool

features—are available.

How to Display UDF File System Parameters

Display UDF file system parameters by using the mkfs command.

1. Become superuser.

2. Display UDF file system parameters.

412

# mkfs -F udfs -m /dev/rdsk/device-name

How to Create a UDF File System

Create a UDF file system by using the mkfs command.

1. Become superuser.

2. Create a UDF file system.

# mkfs -F udfs /dev/rdsk/device-name

3. Verify the UDF file system is created by mounting it. See “How to Mount a

UDF File System” on page 414 for more information.

See mkfs_udfs(1M) for more information.

How to Identify the UDF File System Type

Identify the UDF file system type by using the fstyp command.

1. Become superuser.

2. Determine whether a file system is a UDF file system.

# fstyp -v /rdev/dsk/device-name

How to Check a UDF File System

Check the integrity of a UDF file system by using the fsck command.

1. Become superuser.

2. Check a UDF file system.

# fsck -F udfs /dev/rdsk/device-name

See fsck_udfs(1M) for more information.

Managing File Systems (Overview)

413

How to Mount a UDF File System

Mount a UDF file system.

1. Become superuser.

2. Mount a UDF file system.

# mount -F udfs /dev/dsk/device-name /mount-point

3. Verify the UDF file system is mounted.

# ls /mount-point

See mount_udfs(1M) for more information.

How to Unmount a UDF File System

Unmount a UDF file system.

1. Become superuser.

2. Unmount a UDF file system.

# umount /dev/dsk/device-name

How to Label a Device with a UDF File System

and Volume Name

Create a file system and volume name for a UDF file system.

1. Become superuser.

2. Create a file system and volume name for the UDF file system.

# labelit -F UDFS /dev/rdsk/device-name fsname volume

See labelit_udfs(1M) for more information.

414

Overview of File Systems

A file system is a structure of directories used to organize and store files. The term

file system is used to describe:

A particular type of file system: disk-based, network-based, or virtual

The entire file tree from the root directory downward

The data structure of a disk slice or other media storage device

A portion of a file tree structure that is attached to a mount point on the main file

tree so that it is accessible

Usually, you can tell from context which meaning is intended.

The Solaris operating environment uses the virtual file system (VFS) architecture,

which provides a standard interface for different file system types. The VFS

architecture enables the kernel to handle basic operations, such as reading, writing,

and listing files; and makes it easier to add new file systems.

Administering file systems is one of your most important system administration

tasks. Read this chapter for file system background and planning information. Refer

to other chapters in the System Administration Guide for instructions about the

following tasks:

For This Task ...

See ...

Creating new file systems

Chapter 35 and Chapter 37

Making local and remote files available to

Chapter 36

users

Connecting and configuring new disk

Chapter 28

devices

Designing and implementing a backup

Chapter 42

schedule and restoring files and file systems

as needed

Checking for and correcting file system

Chapter 39

damage

Managing File Systems (Overview)

415

Types of File Systems

The Solaris operating environment supports three types of file systems:

Disk-based

Network-based

Virtual

To identify the type for a particular file system, see “Determining a File System’s

Type” on page 430.

Disk-Based File Systems

Disk-based file systems are stored on physical media such as hard disks, CD-ROMs,

and diskettes. Disk-based file systems can be written in different formats. The

available formats are:

Disk-Based File

System

Format Description

UFS

UNIX file system (based on the BSD Fast File system that was

provided in the 4.3 Tahoe release). UFS is the default disk-based

file system for the Solaris operating environment.

Before you can create a UFS file system on a disk, the disk must

be formatted and divided into slices. See Chapter 28 for complete

information on formatting disks and dividing disks into slices.

HSFS

High Sierra, Rock Ridge, and ISO 9660 file system. High Sierra is

the first CD-ROM file system; ISO 9660 is the official standard

version of the High Sierra File System. The HSFS file system is

used on CD-ROMs, and is a read-only file system. Solaris HSFS

supports Rock Ridge extensions to ISO 9660, which, when present

on a CD-ROM, provide all UFS file system features and file types

except for writability and hard links.

PCFS

PC file system, which allows read/write access to data and

programs on DOS-formatted disks written for DOS-based personal

computers.

UDF

The UDF file system, the industry-standard format for storing

information on the optical media technology called DVD (Digital

Versatile Disc or Digital Video Disc).

Each type of disk-based file system is customarily associated with a particular media

device:

416

UFS with hard disk

HSFS with CD-ROM

PCFS with diskette

UDF with DVD

These associations are not, however, restrictive. For example, CD-ROMs and

diskettes can have UFS file systems created on them.

Network-Based File Systems

Network-based file systems can be accessed over the network. Typically,

network-based file systems reside on one system, typically a server, and are accessed

by other systems across the network. NFS^TM is the only available network-based or

distributed computing file system.

With NFS, you can administer distributed resources (files or directories) by exporting

them from a server and mounting them on individual clients. See “The NFS

Environment” on page 428 for more information.

Virtual File Systems

Virtual file systems are memory-based file systems that provide access to special

kernel information and facilities. Most virtual file systems do not use file system disk

space. However, the Cache File System (CacheFS) uses a file system on the disk to

contain the cache, and some virtual file systems, such as the Temporary File System

(TMPFS), use the swap space on a disk.

The Cache File System

The Cache File System (CacheFS^TM ) can be used to improve performance of remote

file systems or slow devices such as CD-ROM drives. When a file system is cached,

the data read from the remote file system or CD-ROM is stored in a cache on the

local system. See Chapter 37 for detailed information on setting up and

administering CacheFS File Systems.

The Temporary File System

The Temporary File System (TMPFS) uses local memory for file system reads and

writes, which is typically much faster than a UFS file system. Using TMPFS can

improve system performance by saving the cost of reading and writing temporary

files to a local disk or across the network. For example, temporary files are created

when you compile a program, and the operating system generates a lot of disk or

Managing File Systems (Overview)

417

network activity while manipulating these files. Using TMPFS to hold these

temporary files can significantly speed up their creation, manipulation, and deletion.

Files in TMPFS file systems are not permanent. They are deleted when the file

system is unmounted and when the system is shut down or rebooted.

TMPFS is the default file system type for the /tmp directory in the Solaris operating

environment. You can copy or move files into or out of the /tmp directory, just as

you would in a UFS file system.

The TMPFS file system uses swap space as a temporary backing store. If a system

with a TMPFS file system does not have adequate swap space, two problems can

occur:

The TMPFS file system can run out of space, just as a regular file system can fill

up.

Because TMPFS allocates swap space to save file data (if necessary), some

programs might not execute because there is not enough swap space.

See Chapter 35 for information about creating TMPFS file systems. See Chapter 38

for information about increasing swap space.

The Loopback File System

The Loopback File System (LOFS) lets you create a new virtual file system, so you

can access files by using an alternative path name. For example, you can create a

loopback mount of root (/) on /tmp/newroot, which will make the entire file

system hierarchy look like it is duplicated under /tmp/newroot, including any file

systems mounted from NFS servers. All files will be accessible either with a path

name starting from root (/), or with a path name starting from /tmp/newroot.

See Chapter 35 for information on how to create LOFS file systems.

The Process File System

The Process File System (PROCFS) resides in memory. It contains a list of active

processes, by process number, in the /proc directory. Information in the /proc

directory is used by commands like ps. Debuggers and other development tools can

also access the address space of the processes by using file system calls.

Caution - Do not delete the files in the /proc directory. Deleting processes from the

/proc directory will not kill them. Remember, /proc files do not use disk space, so

there is little reason to delete files from this directory.

The /proc directory does not require system administration.

418

Additional Virtual File Systems

These additional types of virtual file systems are listed for your information. They do

not require administration.

Virtual File System

Description

FIFOFS (first-in first-out)

Named pipe files that give processes common access to

data

FDFS (file descriptors)

Provides explicit names for opening files using file

descriptors

NAMEFS

Used mostly by STREAMS for dynamic mounts of file

descriptors on top of files

SPECFS (special)

Provides access to character special and block devices

SWAPFS

File system used by the kernel for swapping

File System Administration Commands

Most file system administration commands have both a generic and a file

system-specific component. You should use the generic commands whenever

possible, which call the file system-specific component. The table below lists the

generic file system administrative commands, which are located in the /usr/sbin

directory.

TABLE 34-1

Generic File System Administrative Commands

Command

Description

Clears inodes

clri(1M)

Reports the number of free disk blocks and files

df(1M)

Lists file names and statistics for a file system

ff(1M)

Managing File Systems (Overview)

419

TABLE 34-1

Generic File System Administrative Commands

(continued)

Command

Description

Checks the integrity of a file system and repairs any damage

fsck(1M)

found

Debugs the file system

fsdb(1M)

Determines the file system type

fstyp(1M)

Lists or provides labels for file systems when copied to tape (for

labelit(1M)

use by the volcopy command only)

Makes a new file system

mkfs(1M)

Mounts local and remote file systems

mount(1M)

Mounts all file systems specified in the virtual file system table

mountall(1M)

(/etc/vfstab)

Generates a list of path names with their i-numbers

ncheck(1M)

Unmounts local and remote file systems

umount(1M)

Unmounts all file systems specified in a virtual file system table

umountall(1M)

(/etc/vfstab)

Makes an image copy of a file system

volcopy(1M)

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How the File System Commands Determine the

File System Type

The generic file system commands determine the file system type by following this

sequence:

1. From the −F option, if supplied.

2. By matching a special device with an entry in /etc/vfstab file (if special is

supplied). For example, fsck first looks for a match against the fsck device

field; if no match is found, it then checks the special device field.

3. By using the default specified in /etc/default/fs for local file systems and in

/etc/dfs/fstypes for remote file systems.

Manual Pages for Generic and Specific Commands

Both the generic and specific commands have manual pages in the man Pages(1M):

System Administration Commands. The specific manual page is a continuation of the

generic manual page. To look at a specific manual page, append an underscore and

the file system type abbreviation to the generic command name. For example, to see

the specific manual page for mounting a UFS file system, type man mount_ufs.

The Default Solaris File Systems

The Solaris file system is hierarchical, starting with the root directory (/) and

continuing downwards through a number of directories. The Solaris installation

process enables you to install a default set of directories and uses a set of

conventions to group similar types of files together. The table below provides a

summary of the default Solaris file systems, and shows the type of each file system.

The root (/) and /usr file systems are both needed to run a system. Some of the

most basic commands from the /usr file system (like mount) are included in the

root (/) file system so that they are available when the system boots or is in

single-user mode and /usr is not mounted. See Chapter 40 for more detailed

information on the default directories for the root (/) and /usr file systems.

Managing File Systems (Overview)

421

TABLE 34-2

The Default Solaris File Systems

File System or

File System

Directory

Type

Description

root (/)

UFS

The top of the hierarchical file tree. The root directory

contains the directories and files critical for system

operation, such as the kernel, the device drivers, and

the programs used to boot the system. It also contains

the mount point directories where local and remote

file systems can be attached to the file tree.

/usr

UFS

System files and directories that can be shared with

other users. Files that run only on certain types of

systems are in the /usr directory (for example,

SPARC executables). Files (such as man pages) that can

be used on all types of systems are in /usr/share.

/export/home

NFS, UFS

The mount point for users’ home directories, which

or /home

store users work files. By default /home is an

automounted file system. On standalone systems, /

home might be a UFS file system on a local disk slice.

/var

UFS

System files and directories that are likely to change or

grow over the life of the local system. These include

system logs, vi and ex backup files, and uucp files.

/opt

NFS, UFS

Mount point for optional, third-party software. On

some systems, /opt might be a UFS file system on a

local disk slice.

/tmp

TMPFS

Temporary files, cleared each time the system is

booted or the /tmp file system is unmounted.

/proc

PROCFS

A list of active processes, by number.

Swap Space

The Solaris operating environment uses some disk slices for temporary storage rather

than for file systems. These slices are called swap slices, or swap space. Swap space is

used as virtual memory storage areas when the system does not have enough

physical memory to handle current processes.

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Since many applications rely on swap space, it is important to know how to plan for,

monitor, and add more swap space when needed. For an overview about swap space

and instructions for adding swap space, see Chapter 38.

The UFS File System

UFS is the default disk-based file system in Solaris operating environment. Most of

the time, when you administer a disk-based file system, you will be administering

UFS file systems. UFS provides the following features:

UFS Feature

Description

State flags

Show the state of the file system: clean, stable, active,

logging, or unknown. These flags eliminate unnecessary

file system checks. If the file system is “clean,” “stable,”

or “logging,” file system checks are not run.

Extended fundamental types

32-bit user ID (UID), group ID (GID), and device numbers.

(EFT)

Large file systems

A UFS file system can be as large as 1 Tbyte (terabyte).

The Solaris operating environment does not provide

striping, which is required to make a logical slice large

enough for a 1-Tbyte file system. However, the Solstice^TM

DiskSuite^TM software, available from Sun, provides this

capability.

Large files

By default, a UFS file system can have regular files larger

than 2 Gbytes (gigabytes). You must explicitly use the

nolargefiles mount option to enforce a 2 Gbyte

maximum file size limit. This limit was removed in the

Solaris 2.6 release.

See Chapter 40 for detailed information about the UFS file system.

Parts of a UFS File System

When you create a UFS file system, the disk slice is divided into cylinder groups,

which are made up of one or more consecutive disk cylinders. The cylinder groups

are then further divided into addressable blocks to control and organize the structure

of the files within the cylinder group. Each type of block has a specific function in

the file system. See “The Structure of UFS File System Cylinder Groups” on page 538

for more detailed information about each type of block.

Managing File Systems (Overview)

423

If you want to customize a file system using arguments with the newfs command or

the mkfs command, see Chapter 40 for information about altering these parameters.

UFS Logging

UFS logging is the process of storing transactions (changes that make up a complete

UFS operation) in a log before the transactions are applied to the UFS file system.

Once a transaction is stored, the transaction can be applied to the file system later.

At reboot, the system discards incomplete transactions, but applies the transactions

for completed operations. The file system remains consistent because only completed

transactions are ever applied. This is true even when a system crashes, which

normally interrupts system calls and introduces inconsistencies into a UFS file

system.

UFS logging provides two advantages. It prevents file systems from becoming

inconsistent, therefore eliminating the need to run fsck. And, because fsck can be

bypassed, UFS logging reduces the time required to reboot a system if it crashes, or

after an unclean halt (see “What fsck Checks and Tries to Repair” on page 510 for

details on unclean halts). UFS logging can significantly reduce the boot time on

systems that have large file systems, which usually take a long time to read and

verify with fsck.

The log created by UFS logging is continually flushed as it fills up. The log is totally

flushed when the file system is unmounted or as a result of the lockfs -f

command.

UFS logging is not enabled by default. To enable UFS logging, you must specify the

−o logging option with the mount command in the /etc/vfstab file or when

mounting the file system. The log is allocated from free blocks on the file system,

and it is sized approximately 1 Mbyte per 1 Gbyte of file system, up to a maximum

of 64 Mbytes. Logging can be enabled on any UFS, including the root (/) file system.

Also, the fsdb command has been updated with new debugging commands to

support UFS logging.

Planning UFS File Systems

When laying out file systems, you need to consider possible conflicting demands.

Here are some suggestions:

Distribute the work load as evenly as possible among different I/O systems and

disk drives. Distribute /export/home and swap space evenly across disks.

Keep pieces of projects or members of groups within the same file system.

Use as few file systems per disk as possible. On the system (or boot) disk, you

should have three file systems: /, /usr, and swap space. On other disks, create

one or, at most, two file systems; one being additional swap space, preferably.

424

Fewer, roomier file systems cause less file fragmentation than many small,

over-crowded file systems. Higher-capacity tape drives and the ability of ufsdump

to handle multiple volumes make it easier to back up larger file systems.

If you have some users who consistently create very small files, consider creating a

separate file system with more inodes. However, most sites do not need to be

concerned about keeping similar types of user files in the same file system.

See Chapter 35 for information on default file system parameters as well as

procedures for creating new UFS file systems.

Mounting and Unmounting File Systems

Before you can access the files on a file system, you need to mount the file system.

Mounting a file system attaches that file system to a directory (mount point) and

makes it available to the system. The root (/) file system is always mounted. Any

other file system can be connected or disconnected from the root (/) file system.

When you mount a file system, any files or directories in the underlying mount point

directory are unavailable as long as the file system is mounted. These files are not

permanently affected by the mounting process, and they become available again

when the file system is unmounted. However, mount directories are typically empty,

because you usually do not want to obscure existing files.

For example, the figure below shows a local file system, starting with a root (/) file

system and subdirectories sbin, etc, and opt.

Managing File Systems (Overview)

425

sbin

etc

opt

SUNWleo

mount

rc0

group

shutdown

ufs

system

ttydefs

mount

Figure 34-1

Sample root (/) File System

Now, say you wanted to access a local file system from the /opt file system that

contains a set of unbundled products.

First, you must create a directory to use as a mount point for the file system you

want to mount, for example, /opt/unbundled. Once the mount point is created,

you can mount the file system (by using the mount command), which makes all of

the files and directories in /opt/unbundled available, as shown in the figure below.

See Chapter 36 for detailed instructions on how to perform these tasks.

Mount Point

File System

sbin

etc

opt

SUNWleo

unbundled

mount

rc0

app1

app2

group

shutdown

ufs

system

file1

ttydefs

file2

mount

file3

Figure 34-2

Mounting a File System

426

The Mounted File System Table

Whenever you mount or unmount a file system, the /etc/mnttab (mount table) file

is modified with the list of currently mounted file systems. You can display the

contents of this file with the cat or more commands, but you cannot edit it. Here is

an example of an /etc/mnttab file:

$ more /etc/mnttab

/dev/dsk/c0t0d0s0

/ ufs rw,intr,largefiles,onerror=panic,suid,dev=2200000 938557523

/proc

proc

dev=3180000

938557522

/dev/fd fd

rw,suid,dev=3240000

938557524

mnttab

/etc/mnttab

mntfs

dev=3340000

938557526

swap

/var/run

tmpfs

dev=1

938557526

swap

/tmp

tmpfs

dev=2

938557529

/dev/dsk/c0t0d0s7 /export/

home ufs rw,intr,largefiles,onerror=panic,suid,dev=2200007 938557529

The Virtual File System Table

It would be a very time-consuming and error-prone task to manually mount file

systems every time you wanted to access them. To fix this, the virtual file system

table (the /etc/vstab file) was created to maintain a list of file systems and how to

mount them. The /etc/vfstab file provides two important features: you can

specify file systems to automatically mount when the system boots, and you can

mount file systems by using only the mount point name, because the /etc/vfstab

file contains the mapping between the mount point and the actual device slice name.

A default /etc/vfstab file is created when you install a system depending on the

selections you make when installing system software; however, you can edit the

/etc/vfstab file on a system whenever you want. To add an entry, the main

information you need to specify is the device where the file system resides, the name

of the mount point, the type of the file system, whether you want it to mount

automatically when the system boots (by using the mountall command), and any

mount options.

The following is an example of an /etc/vfstab file. Comment lines begin with #.

This example shows an /etc/vfstab file for a system with two disks (c0t0d0 and

c0t3d0).

$ more /etc/vfstab

#device

device

mount

fsck

mount mount

#to mount

to fsck

point

type

pass

at boot options

/dev/dsk/c0t0d0s0 /dev/rdsk/c0t0d0s0 /

ufs

/proc

proc

/dev/dsk/c0t0d0s1 -

swap

/tmp

tmpfs

yes

/dev/dsk/c0t0d0s6 /dev/rdsk/c0t0d0s6 /usr

ufs

/dev/dsk/c0t3d0s7 /dev/rdsk/c0t3d0s7 /test

ufs

yes

(continued)

Managing File Systems (Overview)

427

(Continuation)

In the above example, the last entry specifies that a UFS file system on the

/dev/dsk/c0t3d0s7 slice will be automatically mounted on the /test mount

point when the system boots. Note that, for root (/) and /usr, the mount at boot

field value is specified as no, because these file systems are mounted by the kernel as

part of the boot sequence before the mountall command is run.

See Chapter 36 for descriptions of each of the /etc/vfstab fields and information

on how to edit and use the file.

The NFS Environment

NFS is a distributed file system service that can be used to share resources (files or

directories) from one system, typically a server, with other systems across the

network. For example, you might want to share third-party applications or source

files with users on other systems.

NFS makes the actual physical location of the resource irrelevant to the user. Instead

of placing copies of commonly used files on every system, NFS allows you to place

one copy on one system’s disk and let all other systems access it across the network.

Under NFS, remote files are virtually indistinguishable from local ones.

A system becomes an NFS server if it has resources to share over the network. A

server keeps a list of currently shared resources and their access restrictions (such as

read/write or read-only).

When you share a resource, you make it available for mounting by remote systems.

You can share a resource in these ways:

By using the share or shareall command

By adding an entry to the /etc/dfs/dfstab (distributed file system table) file

and rebooting the system

See Chapter 36 for information on how to share resources. See System Administration

Guide, Volume

3 for a complete description of NFS.

428

AutoFS

You can mount NFS file system resources by using a client-side service called

automounting (or AutoFS), which enables a system to automatically mount and

unmount NFS resources whenever you access them. The resource remains mounted

as long as you remain in the directory and are using a file. If the resource is not

accessed for a certain period of time, it is automatically unmounted.

AutoFS provides the following features:

NFS resources don’t need to be mounted when the system boots, which saves

booting time.

Users don’t need to know the root password to mount and unmount NFS

resources.

Network traffic might be reduced, since NFS resources are only mounted when

they are in use.

The AutoFS service is initialized by automount, which is run automatically when a

system is booted. The automount daemon, automountd, runs continuously and is

responsible for the mounting and unmounting of the NFS file systems on an

as-needed basis. By default, the Solaris operating environment automounts /home.

AutoFS works with file systems specified in the name service. This information can be

maintained in NIS, NIS+, or local /etc files. With AutoFS, you can specify multiple

servers to provide the same file system. This way, if one of the servers is down,

AutoFS can try to mount from another machine. You can specify which servers are

preferred for each resource in the maps by assigning each server a weighting factor.

See System Administration Guide, Volume 3 for complete information on how to set

up and administer AutoFS.

The Cache File System (CacheFS)

If you want to improve the performance and scalability of an NFS or CD-ROM file

system, you should use the Cache File System (CacheFS). CacheFS is a general

purpose file system caching mechanism that improves NFS server performance and

scalability by reducing server and network load.

Designed as a layered file system, CacheFS provides the ability to cache one file

system on another. In an NFS environment, CacheFS increases the client per server

ratio, reduces server and network loads, and improves performance for clients on

slow links, such as Point-to-Point Protocol (PPP). You can also combine CacheFS

with the AutoFS service to help boost performance and scalability.

See Chapter 37 for detailed information about CacheFS.

Managing File Systems (Overview)

429

Deciding How to Mount File Systems

The table below provides guidelines on mounting file systems based on how you use

them.

TABLE 34-3

Determining How to Mount File Systems

If You Need to Mount ...

Then You Should Use ...

Local or remote file systems infrequently

The mount command entered manually

from the command line.

Local file systems frequently

The /etc/vfstab file, which will mount

the file system automatically when the

system is booted in multi-user state.

The /etc/vfstab file, which will

Remote file systems frequently, such as home

automatically mount the file system

directories

when the system is booted in multi-user

state.

AutoFS, which will automatically mount

or unmount the file system when you

change into (mount) or out of (unmount)

the directory.

To enhance performance, you can also cache

the remote file systems by using CacheFS.

You can mount a CD-ROM containing a file system by simply inserting it into the

drive (Volume Management will automatically mount it). You can mount a diskette

containing a file system by inserting it into the drive and running the volcheck

command. See Chapter 14 for more information.

Determining a File System’s Type

You can determine a file system’s type by using the following:

The FS type field in the virtual file system table (/etc/vfstab file)

The /etc/default/fs file for local file systems

The /etc/dfs/fstypes file for NFS file systems

How to Determine a File System’s Type

This procedure works whether the file system is mounted or not.

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Sun Microsystems System Administration Guide, Volume 1 (2000) - page 13