Re: Anything to be gained from a 'Postgres Filesystem'? - Mailing list pgsql-performance

From Christopher Browne
Subject Re: Anything to be gained from a 'Postgres Filesystem'?
Date
Msg-id m3is8lt4en.fsf@knuth.knuth.cbbrowne.com
Whole thread Raw
In response to Re: Anything to be gained from a 'Postgres Filesystem'?  ("Leeuw van der, Tim" <tim.leeuwvander@nl.unisys.com>)
Responses Re: Anything to be gained from a 'Postgres Filesystem'?
List pgsql-performance
In an attempt to throw the authorities off his trail, schabios@logi-track.com (Markus Schaber) transmitted:
> We should create a list of those needs, and then communicate those
> to the kernel/fs developers. Then we (as well as other apps) can
> make use of those features where they are available, and use the old
> way everywhere else.

Which kernel/fs developers did you have in mind?  The ones working on
Linux?  Or FreeBSD?  Or DragonflyBSD?  Or Solaris?  Or AIX?

Please keep in mind that many of the PostgreSQL developers are BSD
folk that aren't particularly interested in creating bleeding edge
Linux capabilities.

Furthermore, I'd think long and hard before jumping into such a
_spectacularly_ bleeding edge kind of project.  The reason why you
would want this would be if you needed to get some margin of
performance.  I can't see wanting that without also wanting some
_assurance_ of system reliability, at which point I also want things
like vendor support.

If you've ever contacted Red Hat Software, you'd know that they very
nearly refuse to provide support for any filesystem other than ext3.
Use anything else and they'll make noises about not being able to
assure you of anything at all.

If you need high performance, you'd also want to use interesting sorts
of hardware.  Disk arrays, RAID controllers, that sort of thing.
Vendors of such things don't particularly want to talk to you unless
you're using a "supported" Linux distribution and a "supported"
filesystem.

Jumping into a customized filesystem that neither hardware nor
software vendors would remotely consider supporting just doesn't look
like a viable strategy to me.

> Maybe Reiser4 is a step into the right way, and maybe even a
> postgres plugin for Reiser4 will be worth the effort. Maybe XFS/JFS
> etc. already have such capabilities. Maybe that's completely wrong.

The capabilities tend to be redundant.  They tend to implement vaguely
similar transactional capabilities to what databases have to
implement.  The similarities are not close enough to eliminate either
variety of "commit" as redundant.
--
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