Re: PostgreSQL on XFS experiences?

Jeffrey W. Baker wrote:
> On Thu, 2004-02-26 at 11:46, Holger Marzen wrote:
>
>>On Thu, 26 Feb 2004, Jeffrey W. Baker wrote:
>>
>>>We are using PostgreSQL with the database and xlogs on (separate) XFS
>>>volumes under Linux 2.4.25.  We are simply curious to hear your
>>>experiences with this combination, if you are using it.  In only two
>>>days of heavy activity, we've already been able to corrupt one
>>>database.  We've also seen XFS panic because of inconsistent in-memory
>>>metadata.  Frankly we don't have the highest confidence.
>>
>>I am afraid that xfs in that kernel or your hardware is buggy (probably
>>RAM). A 24h run of memtest86 wouldn't be bad.
>>
>>Since PostgreSQL uses the operating system's calls for file operations
>>as any other program does, it's most probably no PostgreSQL issue.
>
> I don't see why not.

Because Postgres is in use on systems all over the place without problems.

> PostgreSQL could easily have a bug that swaps a
> buffer somewhere, resulting in a corrupt table.

Not easily.  If such a bug existed, I would think that someone else
would have complained about it before now.  I have 3 Postgres servers
under varying levels of usage - all are rock solid reliable, with uptimes
easily over 30 days without problems.  These crashes you describe are
unlikely to be coming from Postgres.

> That we see this only
> on the INSERT path and not the COMMIT path also seems to point towards
> Pg.

Not really.

Have you used something like bonnie++ to test XFS for reliability?
Have you run memtest86 as was suggested?

In my experience, faulty hardware is far more common than what you are
suggesting.

> Anyway, you didn't mention XFS.  Do you have experience using it beneath
> Postgres?

Personally, I have tested it for its performance capabilities, but never
deployed it long-term.  However, in my experience, it works reliably.

--
Bill Moran
Potential Technologies
http://www.potentialtech.com