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Re: Problems with FSFS

From: John Szakmeister <john_at_szakmeister.net>
Date: 2005-10-28 12:14:57 CEST

On Thursday 27 October 2005 05:33, Ryan Schmidt wrote:
> On Oct 27, 2005, at 00:04, Joshua Varner wrote:
> > On 10/26/05, Kahn, Peter <Peter.Kahn@ironmountain.com> wrote:
> >> I do have a question regarding corruption in FSFS. I realize that
> >> it is
> >> less frequent. What's the standard resolution path (recovery?)
> >> and how
> >> often has it failed totally?
> >
> > The way repositories are stored in FSFS if one file is corrupted
> > you will
> > lose only the single revision it represented. If there is no
> > backup, the
> > best bet is to manually fix the file, which can be done in a number of
> > ways, but requires knowledge of the format. I've seen people run
> > svnadmin
> > verify, find the broken revision, send it to a dev (who volunteered
> > to look)
> > and they fixed the file.

I have done such a thing, and generally don't mind, as long as I don't have
other pressing deadlines at work. :-)

> > Failure rate statistics are not something I have, might be a good
> > idea to
> > do a survey at some point.
> In my ~9 months of reading this list, I've heard of dozens of
> instances (far too many to recall) of BDB repositories getting
> wedged, and a handful of instances of unrecoverable corruption,
> versus zero such problems with FSFS. That is to say, it is not
> possible for FSFS repositories to get wedged; wedging is a "feature"
> of BerkeleyDB. The fact that the Subversion developers have made FSFS
> the default as of Subversion 1.2.0 should also speak for its stability.

What do you mean by unrecoverable corruption? If you mean that people lost
their repositories entirely, I don't have any recollection of such a thing.
If you mean that in order to recover and move on, they had to suffer a loss
of history or data in a particular file, then both FSFS and BDB have suffered
from those situations (I've recovered 4 FSFS repositories in the past several
months). That said, at least one of the FSFS corruptions turned out to be a
hardware related failure.

In my experience, I've had a great deal of success with both BDB. Both are
equally capable and stable when set up properly. If you suffer from wedges,
or are using multiple access methods, then by far, FSFS is the way to go.


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Received on Fri Oct 28 12:18:18 2005

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