Re: Restoring FSFS repository from backup question

Kyle Kline wrote:

> The docs indicate that FSFS is suited well for backup schemes, with
> the caveat that if a backup takes place while a commit is in progress,
> the db/current file may not indicate the true current rev in the
> db/revs directory.

Yep. The fact that old versions are represented by unchanging files works
out well.

> My backup software does not allow me to specify orders of files to
> avoid this, and I would like to avoid doing a hotcopy due to the size
> of the repository.

Of course, most backup schemes get this write by accidental good design :-)
Proceeding alphabetically (as most do) 'current' < 'revs'. Proceeding by
processing a folder, then processing its subfolders will also get it right.
So most backup tools do this correctly without knowing that they are doing
it right :-)

> If I needed to restore and my db/current file is out of date, Is it as
> simple as editing the file? I notice there are three values in the
> file, <current-rev> <unknown -- hash?> <unknown> ......

Yes it is. FWIW, the fsfs format is described in detail at
http://svn.collab.net/viewcvs/svn/trunk/subversion/libsvn_fs_fs/structure?rev=13571&view=markup

The current file is
<youngest-revision> <next-node-id> <next-copy-id>\n

I would assume it's fine to leave next-node-id and next-copy-id at whatever
values they have, and just fix youngest-revision, since a value that's
'from the future' vs. the rest of the baCkup is still unique.

> Thx,
> Kyle

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Received on Sun May 1 03:49:56 2005