Given that /usr is large enough to be reduced what is the best way to accomplish the task. Aren't command that are necessary to accomplish the reduce in /usr/bin - /usr/sbin ?
If you have Online JFS licensed, then you may be able to do this while the filesytem is mounted. Generally you are advised to degragment the filesystem first. It is more likely that the subsequent attempt to shrink the filesystem will succeed if you do this. If files reside and are inuse in the region destined for reduction, the reduction will fail. The latest (3.3) version of JFS does much better at this than earlier version, I understand.
If you do not have the online JFS component, then you must backup the filesystem's data; unmount the filesystem; lvreduce;, recreate; and reload the contents.
If you have online jfs can do the following 1. defrag your file system fsadm -F vxfs -d -e -s /var 2. Reduce the file system Example: you want to go from 1G to 500Mb Calculate size in bytes 500*1024=510000 ( I didn't use a calculater but you get the idea :) 0
fsadm -F vxfs -b 510000 /var
If this works then you can go to the next step 3. Reduce the lvol bdf - get new size of fs and divide by 1024 to get Mb of filesystem Use the newsize + 4m so if the new sise is 512M use 516M so you don't destroy any data in your file system.
lvreduce -L /dev/vgXX/lvol# example lvreduce -L 516 /dev/vgXX/lvol#
In addition, to clarify my question, if I will be using the mount, cpio, etc... commands to do the restore, once I do the lvreduce on /usr, will I still be able to use those commands ?
OK. 'vxfs' is also know as "JFS", but JFS has a base and an online component. If you don't have the online component (no "online" noted in: 'swlist -l bundle|grep -i jfs' output) then you will need to drop to single-user mode and use the commands in /sbin.
I suggest that booting to single-user mode is easist; then doing your LVM maintenance is the easiest, cleanest way to start. You could also do your backups there (with /usr mounted) to be sure of a quiet system.
As always, make very, very sure you have a good backup.
The point I do not understand is once I do the lvreduce and the newfs to reduce the /usr file system, the file /usr/bin/cpio I need to restore the backup will no longer exist. Even if I were to copy /usr/bin/cpio to another file system and try to execute the cpio command from there I receive an error message.
'tar' resides in /sbin as does 'frecover'. You could use either 'tar' or 'fbackup' while /usr is mounted, and then use '/sbin/tar' or '/sbin/frecover' to restore. Yes, 'cpio' only exists in /usr.
