AIX Filesystem tips

1) How to view all filesystems on a machine ?

"lsfs" is the command to list all the filesystems on a server. Alternatively, you can also view /etc/filesystems.

aix23:# lsfs -l
Name            Nodename   Mount Pt               VFS   Size    Options    Auto Accounting
/dev/hd4        --         /                      jfs2  131072  --         yes  no
/dev/hd1        --         /home                  jfs2  131072  --         yes  no
/dev/hd2        --         /usr                   jfs2  5111808 --         yes  no
/dev/hd9var     --         /var                   jfs2  2097152 --         yes  no
/dev/hd3        --         /tmp                   jfs2  4325376 --         yes  no
/proc           --         /proc                  procfs --      --         yes  no
/dev/hd10opt    --         /opt                   jfs2  2097152 --         yes  no
/dev/fslv00     --         /ds1                   jfs2  2097152 rw         yes  no
/vol/d2         nfs12      /d2                    nfs   --      rw,nointr,rsize=32768,wsize=32768 yes  no
aix23:#


2) How do you enable largefile support in AIX?

On file /etc/security/limits , change the value of "fsize" to -1 . "-1" denotes unlimited. Log-off and login , stop & start applications to make largefiles work.

3) Creating filesystem in AIX

The crfs command creates a file system on a logical volume within a previously created volume group. A new logical volume is created for the file system and an entry for the file system is put into the /etc/filesystems file.

The options :

-v : Filesystem type
-m : mount point
-A : mount automatically on reboot or no
-p : Mount as ro/rw
-l : size of log volume in case of jfs
-g : Volume group name.
-a size : Size of filesystem

Example :

# crfs  -v jfs2 -m /d1 -A yes -p rw -l 1 -a size=100M -g rootvg
File system created successfully.
130864 kilobytes total disk space.
New File System size is 262144
#
# mount /d1
# df -m /d1
Filesystem    MB blocks      Free %Used    Iused %Iused Mounted on
/dev/fslv00      128.00    127.66    1%        4     1% /d1
#

4) Extending a filesystem

The chfs command changes the attributes of a file system.  This command can be used to extend the filesystem.

# chfs -a size=200M /d1
Filesystem size changed to 524288
# df -m /d1
Filesystem    MB blocks      Free %Used    Iused %Iused Mounted on
/dev/fslv00      256.00    255.64    1%        4     1% /d1

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