[linux-lvm] LVM mirrors and drive failure
jbrassow at redhat.com
Tue Aug 21 22:47:30 UTC 2007
On Aug 21, 2007, at 2:27 PM, Stuart D. Gathman wrote:
> The current LVM mirror code creates 3 (or more - assume just 2
> copies for discussion) pieces: copy0, copy1, log. It is obvious what
> should and probably does happen if the PV for copy0 or copy1 goes
> But what happens if the PV for log goes away? Does it convert to a
> log? When you reboot, does it do a full sync, like with a memory log?
> Which copy is copied from and which is copied to for the sync?
Yes, it converts to an in-memory log. Yes, you will do a full sync
if you reboot.
We are working on code to use hot-spares. In that case, the log
would simply be replaced.
Also, we are working on some allocation changes so you can have a log
and 2 copies on just two devices.
Best thing to do now is to replace the log manually if it fails. If
the mirror is in-sync, that will be preserved, and the mirror will
not need to be resynced.
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