Procedure to extend the size of filesystem using JFS:

"df" to see the filesystem, it's current size, % utilization and the name of it's logical volume

1. "lslv <logical_volume>" to show information about the logical volume including it's volume group name.
2. "lsvg <volume_group>" to show information about the volume group, including number of free pp's and the pp size
3. If there are not enough free pp's then see below for procedure to add a disk to a volume group.
   
4. "chfs -a size= +4194304 <MOUNT_POINT>" to grow the filesystem by 2 GB (4194304=2*1024*1024*1024/512)
• NOTE:  Growing the file system will automatically grow the logical volume
5. df" shows the file system's current size is 2 GB more than before.

Troubleshooting extending the size of a filesystem using JFS:

• Error Message:  0516-787 extendlv: Maximum allocation for logical volume <LV_Name> is 512.
• Maximum number of LPs for the logical volume has been exceeded - must increase the allocation
• Calculate the number of LPs needed = LV Size in MB / LP size in MB
• chlv -x <new_max_lps> <logical_volume>