Re: ERROR: unexpected data beyond EOF in block XXXXX of relation "file"

On Sun, Sep 28, 2008 at 11:51:49AM -0700, austijc wrote:
>
> That's going to be a problem for the continued viability of
> Postgres.

Funny, I thought running a DBMS over a known-unreliable storage system
was a problem for the continued viability of Oracle. When, not if,
people lose enough data to this silliness, they'll be thinking hard
about how to get Oracle out and something reliable in.

> Clustered systems using a NAS for data is a pretty common
> configuration these days. Oracle specifically supports it and even
> complains if your NFS mount options are not correct. Our Oracle
> DBs run great in this same configuration and are a good 10-20 times
> faster than the local disk performance along with the quick
> take-over capability if a system goes belly up.

Oracle stores more state to the disk than PostgreSQL does, which has
significant down sides. There are more effective ways of handling
uptime requirements than jamming NFS into the picture. Maybe it's
just my failure of imagination, but I can't think of a *less*
effective one.

> I'll try to isolate this problem with a simple C program to tell me
> what software layer to look at. Hopefully it's just a configuration
> issue.

It's not. The issue is that NFS is broken garbage from a DBMS, and,
it's pretty easy to argue, just about any other perspective.

Cheers,
David.

>
> Tom Lane-2 wrote:
> >
> > austijc <jaustin(at)jasononthe(dot)net> writes:
> >> The question is can anyone more familiar with this tell me what's going
> >> on
> >> here? I don't know if this is a Postgres, Sun, or NetApp issue. Could
> >> it
> >> be a work around for an old Linux bug causing an issue with acceptable
> >> behavior of the NetApp device?
> >
> > People who try to run databases over NFS usually regret it eventually ;-)
> >
> > All I can say is that this error message has never before been reported
> > by anyone who wasn't exposed to that lseek-inconsistency kernel bug.
> > I am not finding it too hard to believe that NFS might be vulnerable to
> > similar misbehavior.
> >
> > regards, tom lane
> >
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> >
>
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