Not enough free space to shrink the file system issue in AIX

Recently got an issue in reducing jfs2 filesystem  with osverion 6.1 and have enough space to reduce filesystem.

root@umaix /tmp>df -g /orafs1
Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/oralv1   100.00    75.00   25%      555     1%  /orafs1

root@umaix /tmp>chfs -a size=-15G /orafs1
chfs: There is not enough free space to shrink the file system.

This issue will occur whenever you try to reduce big chunk of data ( in this case 15GB) that may not be contiguous in the file-system because you have files scatted everywhere.

Try   the following methods one by one until your issue fixed

1. Try to defrag the FS:

#defragfs -s /orafs1

2. Reduce in smaller chunks:

If you still can't reduce it after this. Try reducing the filesystem  in smaller chunks. Instead of 15G at a time, try reducing 1 or 2 gigs. Then, repeat the operation.

3. Check the processes:

Sometimes processes open big files and use lots of temporary space in those filesystem.
You could check processes/applications running against the filesystem and stop them temporarily, if you can.

#fuser -cu[x] <filsystem>

4. Move the large files and try shrink

Try looking for files large using the find cmd and move them out temporarily, just to see if we can shrink the fs without them:

#find /<filesystem> -xdev -size +2048 -ls|sort -r +10|pg

Finally the last method, the alternative approach if any one of above methods are not working then go for filesystem recreation.

==> You should be very care full , need to take fs backup and as well as approach application before removing the filelsystem.

5) Recreate filesystem:

• - Take databackup of the fielsystem  ( very Important,dont skip this )
  Either you can take using your backup tools like TSM / netbackup or move data to a temporary   directory


• - Remove the  filesystem  (  #rmfs /orafs)
• - Create the filesystem again
   #mklv -y oralv1 -t jfs2 oravg 600  ( in this case we need 75GB and pp size is 128)
   #crfs -v jfs2 -d oralv1 -m /orafs1 -A yes  (create orafs1 filesystem)


• - Restore data to the filesystem
• - Verify fs size

root@umaix /tmp>df -g /orafs1
Filesystem    GB blocks      Free %Used    Iused %Iused Mounted on
/dev/oralv1   75.00    50.00   33%      555     1%  /orafs1