[Pvfs2-users] pvfs2 stability

[Rob Ross]

we should add this to our FAQ...

Mark Bartelt wrote:
>>>  Fedora comes with some cron jobs activated,
>>>  in particular the cron.daily:
> 
> Indeed; not just Fedora, but most (all?) Linux
> distros seem to come littered with all sorts of
> cron jobs of questionable value.  The old UNIX
> "minimalist" approach (letting people add stuff
> if they wanted) seems to have been replaced with
> a "let's try to do nearly everything" one, which
> forces people to remove things they don't really
> _want_ to have enabled.  But I'll stop ranting ...
> 
> My point is that we were burned by this, thanks
> to SuSE's /etc/cron.daily/updatedb (performs the
> same function as /etc/cron.daily/slocate.cron on
> Fedora):  We'd seen horribly sluggish performance
> on our PVFS filesystems once every day, until we
> realized it was "updatedb" crunching through tens
> of terabytes of files.  And it was even worse, as
> "updatedb" fired off at the same time on close to
> ninety systems at once!
> 
> The fix was obvious, namely adding "/pvfs" to the
> "UPDATEDB_PRUNEPATHS" in /etc/sysconfig/locate (on
> Fedora, it's "PRUNEPATHS" in /etc/updatedb.conf).
> 
> We didn't see any failures (network, PVFS, or any
> other issues) per se; just awful performance until
> we told the cron job not to descend into the /pvfs
> hierarchy.
> 
> So if I were you, I'd still be a bit worried about
> the fact the failures happened at all.  It might be
> worth doing some controlled heavy pounding of your
> PVFS hierarchy (e.g. just a massive "find" to walk
> the entire PVFS filesystem; or better, a bunch of
> them going on simultaneously, launched from a lot
> of different systems) to see whether the problems
> recur ...
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