[linux-lvm] e2fsadm and snapshots?

[Andreas Dilger]

On Oct 31, 2002  14:57 -0800, Jim King wrote:
> I'm trying to set up snapshots on my LVM volumes sort of like the way
> Network Appliance does it... with hourly rotating snapshots. The obvious
> problem is that the snapshots do not dynamically size. This is a real
> issue, because snapshots no longer protect us from someone (for example)
> deleting a huge directory accidently.
> 
> To solve that I'm trying to figure a way to have them dynamically size
> -- with a script that checks how full they are and grows them
> automatically if they start to fill up.
> 
> Problem:
> --------
> If I do e2fsadm on a normal LVM volume it works, but if I do e2fsadm on
> a snapshot I get something like:
> 
>   /sbin/e2fsck: Permission denied while trying to open
>      /dev/data1/.mer_dev.hourly.3
>   You must have r/w access to the filesystem or be root
> 
> Now I'm logged in as root, and the filesystem is unmounted. Ideas? I'm
> suspecting it's because the snapshot is ro, but is there a way to work
> around this?

The LVM snapshot is the whole filesystem (with only the parts that
actually change being written to the snapshot LV) - no need to change
the filesystem size at all.  All you need to change is the LV size.

Cheers, Andreas
--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/