Re: LVM and disk failure
On Sat, 2006-01-07 at 20:20, Daniel Webb wrote:
> What happens when you have a 2-disk LVM volume group and disk 1 fails?
> Obviously this will depend on the filesystem you put on top of the volume,
> right? So which filesystems will recover gracefully if you chop them in half
> like that?
>
> It's a little disturbing that in all the documentation I've read on LVM this
> is never mentioned, and yet it seems to destroy the main purpose of lvm: to be
> able to add and remove disks to a volume easily. Each physical volume you add
> makes it that much more likely that you'll lose the whole thing. Sure, you
> can put it on top of RAID, but now you lost your size flexibility because RAID
> isn't so easy to resize (or is it?). The snapshots feature is nice, that's
> all I'll use it for until I find a satisfactory answer to this question.
If you've got enough spindles, each physical volume is typically a RAID1
or RAID5. Then you can add and remove physical volumes from
your volume group as needed. A single disk failure is harmless.
Other than adding and removing physical volumes you don't resize
the volume group. The logical volumes are readily resizable, as
are some of the filesystems (e.g. ext2/3) which they can contain.
--Mike Bird
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