Repository on LVM filesystem snapshot

Matt Nordhoff mnordhoff at mattnordhoff.com
Sun Jul 5 15:37:53 CDT 2009


Matt Mackall wrote:
> On Sun, Jul 05, 2009 at 04:17:22PM +0200, Lasse Kliemann wrote:
>> Under Linux, LVM allows to take a snapshot of a filesystem.  
>> (Solaris had a similar feature for years.) This is used in order 
>> to take a backup (with rsync, tar, etc.) reflecting the 
>> filesystem's state at a particular time. AFAIK there is no other 
>> way to get that on a live filesystem.
>>
>> Although the snapshot is consistent in that respect that it does 
>> reflect a state of the filesystem at a point of time, this does 
>> not mean that is is also consistent from the viewpoint of 
>> applications. For instance, suppose there is a Mercurial 
>> repository on the filesystem, and the snapshot is taken during a 
>> transaction or similar. Then the original filesystem is lost 
>> (say, due to hardware failure) and the admin restores it using a 
>> copy taken from the snapshot. Is it guaranteed that this gives 
>> again a fully-functional repository?
> 
> Yes.

It's still a good idea to run "hg recover", no?
-- 


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