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Re: svn: bdb: PANIC / Reliability?

From: John Szakmeister <john_at_szakmeister.net>
Date: 2005-05-09 11:22:25 CEST

On Monday 09 May 2005 04:13, Georg Wittenburg wrote:
> Good morning,
>
> I switched over from CVS to SVN 1.1.4 about a month ago and have been
> accessing my repository using file:/// and svn+ssh:// as one of a group
> of two people that have write access. No fancy stuff, imho. While my
> last commit before this weekend went in without trouble, now my
> repository seems to be corrupt.
>
> Actually, I already recovered once this Saturday using a procedure I
> found online (sorry, no URL) that included rm __db.00*, rm
> log.000000001*, db_recover -cv in the db directory. Things worked fine
> after that and I was able to commit and update. I do have a backup from
> that time, so my data is safe and I'm not in trouble. However, I DO
> worry about the reliability of SVN because this morning I got the
> following errors (and I don't think my first recovery attempt was
> flawed, because things were working fine just afterwards):
>
> $svn up
> svn: Berkeley DB error while checkpointing after Berkeley DB
> transaction for filesystem /home/bude/wittenbu/svn/db:
> Invalid argument
> svn: bdb: DB_ENV->log_flush: LSN of 19/323156 past current end-of-log
> of 1/38823
> svn: bdb: Database environment corrupt; the wrong log files may have
> been removed or incompatible database files imported from another
> environment svn: bdb: representations: unable to flush page: 0
> svn: bdb: txn_checkpoint: failed to flush the buffer cache Invalid
> argument

What version of BDB are you using, and have you recently upgraded it at
all? Also, does the repository lie on a local filesystem, or are you
using it on an remote share of some sort?

> $ svnadmin recover .
> Repository lock acquired.
> Please wait; recovering the repository may take some time...
> svn: DB_RUNRECOVERY: Fatal error, run database recovery
> svn: bdb: Log sequence error: page LSN 1 7802; previous LSN 19 316241
> svn: bdb: Recovery function for LSN 1 7802 failed on forward pass
> svn: bdb: PANIC: Invalid argument
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
> svn: bdb: PANIC: fatal region error detected; run recovery
>
> Usually I wouldn't mind helping the developers to iron this out, except
> for the fact the I'm currently writing my master thesis and from an
> users perspective just need a SCM system that is ROCK SOLID!

I understand the frustration, but there is something wrong with your set
up. I've been using the BDB backend for quite some time (over 2 years
now), and have had exactly 1 problem... it was my fault.

> I'm sorry to say that SVN just doesn't seem to be there yet. Further,
> the entry in the FAQ about DB_RUNRECOVERY isn't particularly
> encouraging, as it tells me that my data not only gets corrupted by
> processes crashing but also by incorrect permissions. I'm sorry for the
> people who put a lot of effort into SVN, but my perception is that this
> is somewhat too fragile for production use, or rather at least for me.

Again, it's fine if you set things up correctly. Admittedly, that's
easier if you use the FSFS backend.

> Now, I fixed my repository AGAIN by repeating the three steps pointed
> out above. However, I'm getting quite close to switching back to CVS
> because from my perspective as an user, this trouble is just not worth
> it.
>
> While I guess that this mailing list gets a lot of noise about these
> kind of problems (Google gives me 318 hits for the first part of the
> subject of this mail), I'd appreciate if you could share some insight,
> particularly whether my problems are just unique events that'll never
> happen to anyone and I was just being unlucky, or whether I'd just have
> to expect these kind of problems when using SVN. If there's interest,
> I've also tarballs of the corrupted and fixed repositories.

There is one of several problems. More than likely the repository is
being stored on a share (don't do that with BDB), or you have a buggy
version of BDB (we seem to bring out several bugs in the 4.1.x line).
The only other item that tends to catch people is upgrades. If BDB was
upgraded, you need to do a few things to your repository to use the new
version of BDB.

Honestly, if you're using svn+ssh://, and FSFS repository is probably the
best way to go. Using svn+ssh:// correctly generally requires a script
to ensure that the permissions are correct. FSFS can do it without said
script.

-John

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Received on Mon May 9 11:29:57 2005

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