Re: svn hotcopy vs. LVM snapshot

Thanks for the reply.

I asked:
>> Has anyone investigated the relative merits of "svn hotcopy" and LVM
>> snapshots?

Phillip Susi wrote:
> The problem is that the snapshot is in an inconsistent state, as if the
> machine had crashed at that moment. You will need to fsck the snapshot
> to make sure the filesystem is ok before mounting it.

I believe that there is some "magic" in the LVM stuff to make this safe,
i.e. the filesystem is told to do some sort of flush before the snapshot
is taken, or something. The feature is designed specifically for things
like backups. (I'm hoping that someone who is reading this will know a
definitive answer...)

> In short, it is safer to svn hotcopy, because this guarantees that the
> saved information is consistent; i.e. does not contain half of a commit
> that was in progress.

In what sense is a "half commit" possible? It's atomic; by definition,
either a commit has happened, or it hasn't. If it's possible to
snapshot "during" a commit, surely subversion is broken. Or am I
missing something?

Cheers,

--Phil.

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Received on Tue Nov 22 20:38:58 2005