fsexpand - expand existing file systems

fsexpand enables file systems to be expanded by PAM pages or cylinder groups.

The file systems must be unmounted (see umount).

Syntax

fsexpand[ -i][ -p pam_pages| -c cylinder_groups][-N] device

-i

Outputs file system information. Output takes place to stdout. In particular information is output on how ideal an expansion is, e.g. to prevent unused PAM pages in the expanded file system. In conjunction with the -p or -c option, information is output before the expansion (source file system) and after the expansion (target system).

-p pam_pages

Expansion of a file system by PAM pages.

The file system is expanded by the specified number of PAM pages.

-c cylinder_groups

Expansion of a file system by cylinder groups.

The file system is expanded by the specified number of cylinder groups. The size of a cylinder group in the source file system can be ascertained before expansion using fsexpand -i. Up to a file size of a little more than 2 GB, the size is 2048 PAM pages. From 2 GB on, the size increases. With a file size of 4 GB, for example, it is then 4096 PAM pages.

-N

If applicable, skip the compactification (see hints below).

device

Device name /dev/rdsk/... (character-oriented device only, i.e. not /dev/dsk) or BS2000 file name.

device must be writeable when an expansion is to take place. If the file system is located on the HOME pubset, the BS2000 file name (with or without catid) must match the notation in the /etc/partitions file.

Hints

The fsexpand command is not supported for bs2fs file systems.

A file system is expanded in two steps:

1. Physical expansion

2. Combining administrative units of the file system (known as cylinder groups) to form larger units (compactification).

Compactification is performed only if the expanded file system is greater than 2 GB and at least double the size of the original file system.

Compactification increases the runtime of fsexpand considerably. However, it has the advantage that performance gains can be achieved when using the file system, since the memory and CPU time requirements are lower due to the combination of the administrative units.

Example

# df -h /home/foo
Filesystem                   Size    Used   Avail     Use% Mounted on
/dev/dsk/18                  365M    210M    119M      64% /home/foo 

# umount /home/foo

# fsexpand -i /dev/rdsk/18

device /dev/rdsk/18 in Containerfile: $SYSROOT.FS.HOME.FOO

size of BS2000 Containerfile (PP):   200010
size used for POSIX filesystem (PP):         200004
unused in Containerfile (PP):                6
Cylindergroups in filesystem:                98
Cylinders in cylindergroup:          16
Cylinders in last cylindergroup:    11
size of a cylindergroup (PP):                2048
size of last cylindergroup (PP):    1348
inodes per cylindergroup:            2048
inodes total:                                200704
datablocks(4K) in filesystem:                93333
        free blocks(4K)         directories             free inodes
        39586                   242                     198694
optimal values for expansion of container: 694 PP + N * 2048 PP

# fsexpand -p 100000 '$SYSROOT.FS.HOME.FOO'

device /dev/rdsk/18 in Containerfile: $SYSROOT.FS.HOME.FOO

size of BS2000 Containerfile (PP):   300006
size used for POSIX filesystem (PP):         300006
unused in Containerfile (PP):                0
Cylindergroups in filesystem:                147
Cylinders in cylindergroup:          16
Cylinders in last cylindergroup:    8
size of a cylindergroup (PP):                2048
size of last cylindergroup (PP):    998
inodes per cylindergroup:            2048
inodes total:                                301056
datablocks(4K) in filesystem:                140002
        free blocks(4K)         directories             free inodes
        86255                   242                     299046
optimal values for expansion of container: 1050 PP + N * 2048 PP

# mount /home/foo

# df -h /home/foo
Filesystem                   Size    Used   Avail     Use% Mounted on
/dev/dsk/18                  547M    210M    283M      43% /home/foo