Alvin Chang wrote: > On 05/01/07, Aleksandar Milivojevic <alex at 8-p.ca> wrote: >> I've used it, and it works correctly (and it is available in CentOS >> 4.4). It shrinks file system as it should. The only things Paul should >> be careful is to first shrink file system, than logical volume and to >> correctly calculate file system size and by how many extents he can >> shrink logical volume. If he shrinks logical volume too much, he might >> end up loosing data. Running fsck in non-destructive mode (fsck -N) >> and/or attempting to mount file system read-only after he shrinks >> logical volume might be a good idea to test all is OK. > A little technique you can use is: > 1. shrink the file system to the size slightly less than what you > really want > 2. reduce LV to the size that is what you really want > 3. expand the file system to the size of the LV (usually the resize > program can be told to expand the file system to maximum available > space automatically on the LV.) > That sounds like a pretty healthy tip! Keep in mind that with a large LV, the slowest part of this process is often the fsck -f step. The resize2fs command is not nearly as slow as the fsck -f. But on a large LV, you prolly want to show the progress bar during the resize, so do a resize2fs -p, because I know I get nervous when I don't see output from a long running command. On production systems, I've learned to have enough space to have one empty LV that can hold any of the other LVs so you can cleverly remount a copy of the LV you want to either fsck or recreate. I don't want to have a 2-hour reboot after 200 days uptime just to have my filesystem force a fsck -f on you when you very like least want it. Recreating a LV is a clever way to get around doing regular fscking, unless you tune your filesystem check way out to 3 years and 999 reboots or whatnot. Jed