Re: file system and raid performance

Scott Marlowe wrote:
> On Sun, Dec 7, 2008 at 10:59 PM, M. Edward (Ed) Borasky
> <znmeb@cesmail.net> wrote:
>> Ah, but shouldn't a PostgreSQL (or any other database, for that matter)
>> have its own set of filesystems tuned to the application's I/O patterns?
>> Sure, there are some people who need to have all of their eggs in one
>> basket because they can't afford multiple baskets. For them, maybe the
>> OS defaults are the right choice. But if you're building a
>> database-specific server, you can optimize the I/O for that.
> 
> It's really about a cost / benefits analysis.  20 years ago file
> systems were slow and buggy and a database could, with little work,
> outperform them.  Nowadays, not so much.  I'm guessing that the extra
> cost and effort of maintaining a file system for pgsql outweighs any
> real gain you're likely to see performance wise.
> 
> But I'm sure that if you implemented one that outran XFS / ZFS / ext3
> et. al. people would want to hear about it.
> 
I guess I wasn't clear -- I didn't mean a PostgreSQL-specific filesystem
design, although BTRFS does have some things that are "RDBMS-friendly".
I meant that one should hand-tune existing filesystems / hardware for
optimum performance on specific workloads. The tablespaces in PostgreSQL
give you that kind of potential granularity, I think.

-- 
M. Edward (Ed) Borasky, FBG, AB, PTA, PGS, MS, MNLP, NST, ACMC(P), WOM

"A mathematician is a device for turning coffee into theorems." --
Alfréd Rényi via Paul Erdős