Is it possible to convert from a JFS to a JFS2 filesystem?
No, a JFS filesystem cannot be converted to become a JFS2 filesystem.
The two types of filesystems have completely different structures and inode allocation methods. There are three recognized methods to move data from a JFS to a JFS2 filesystem.
1. Copy With Parallel Filesystems
If you have the space, creating a second filesystem and simply copying the data is the easiest way.
# crfs -v jfs2 -g myvg -a size=20G -A yes -m /newfilesystem
This will create a 20GB filesystem in volume group “myvg” with mount point “/newfilesystem”.
Mount the filesystem:
# mount /newfilesystem
Copy the data from your existing filesystem to it, with a command similar to:
# cd /mydata; pax -x pax -w * | (cd /newfilesystem; pax -v -r )
(Using pax will preserve sparseness that may exist in database files. See technote T1000145 “About Sparse Files” for more information on this topic)
Unmount the current filesystem and rename it:
# unmount /mydata
# chfs -m /oldfilesystem /mydata
Rename the mount point of the new filesystem and mount it::
# chfs -m /mydata /newfilesystem
# mount /mydata
At this point test your application or check over your data. If all is well remove the old filesystem:
# rmfs /oldfilesystem
2. Backup and Recreate
Back up your data on the original filesystem, remove it and recreate as JFS2. Use this when you do not have enough disk space to have the same filesystem existing in parallel.
Back up the data using whatever command you usually use to back up the files.
Unmount and remove the old filesystem:
# umount /mydata
# rmfs /mydata
Create the filesystem again:
# crfs -v jfs2 -g myvg -a size=20G -A yes -m /mydata
# mount /mydata
Restore your data to /mydata
3. Alternate Disk Copy for Rootvg
If your filesystems are rootvg ones, neither of these methods will work. However you can use alt-disk copy to create a new rootvg. Using the -T flag will recreate the filesystems as JFS2:
Indicates that you want to convert JFS file systems to JFS2 file
systems during the process of recreating the rootvg volume group
on target disks.
# alt_disk_copy -T -d hdiskX
where hdiskX is an unused disk not belonging to any volume group.