Re: Raw devices vs. Filesystems - Mailing list pgsql-admin

From Marsh Ray
Subject Re: Raw devices vs. Filesystems
Date
Msg-id 40736DE6.6060200@mysteray.com
Whole thread Raw
In response to Re: Raw devices vs. Filesystems  ("Gregory S. Williamson" <gsw@globexplorer.com>)
List pgsql-admin
 > gsw@globexplorer.com ("Gregory S. Williamson") writes:
 >>No point to beating a dead horse (other than the sheer joy of the
 >>thing) since postgres does not have raw device support, but ...  raw
 >>devices, at least on solaris, are about 10 times as fast as cooked
 >>file systems for Informix. This might still be a gain for postgres'
 >>performance, but the portability issues remain.

 > From: Chris Browne [mailto:cbbrowne@acm.org]
 > That claim seems really rather remarkable.
 > It implies an entirely stunning degree of inefficiency in the
 > implementation of filesystems on Solaris.
 > The amount of indirection involved in walking through i-nodes and such
 > is something I would expect to introduce some percentage of
 > performance loss, but for it to introduce overhead of over 900%
 > presumably implies that Sun (and/or Veritas) got something really
 > horribly wrong.

Gregory S. Williamson wrote:
> Remarkable, perhaps, to you. Not in the Informix world. But
 > irrelevant to postgres, no ?

I too am a little surprised by those numbers, but I think the potential
for a performance gain of that order is relevant.

As I once heard someone remark: "When show up at a pool hall talking
those kind of odds, well, people start making phone calls."

- Marsh


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