Horton

Re: [HACKERS] Performance while loading data and indexing

Rod Taylor <rbt@rbt.ca>

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From: Rod Taylor <rbt@rbt.ca>
To: Bruce Momjian <pgman@candle.pha.pa.us>
Cc: Neil Conway <neilc@samurai.com>, Greg Copeland <greg@CopelandConsulting.Net>, shridhar_daithankar@persistent.co.in, PostgresSQL Hackers Mailing List <pgsql-hackers@postgresql.org>, PostgresSQL General Mailing List <pgsql-general@postgresql.org>
Date: 2002-09-26T22:03:36Z
Lists: pgsql-hackers, pgsql-performance, pgsql-general 
On Thu, 2002-09-26 at 17:47, Bruce Momjian wrote:
> Rod Taylor wrote:
> > > Yes, before UFS had soft updates, the synchronous nature of UFS made it
> > > slower than ext2, but now with soft updates, that performance difference
> > > is gone so you have two files systems, ext2 and ufs, similar peformance,
> > > but one is crash-safe and the other is not.
> > 
> > Note entirely true.  ufs is both crash-safe and quick-rebootable.  You
> > do need to fsck at some point, but not prior to mounting it.  Any
> > corrupt blocks are empty, and are easy to avoid.
> 
> I am assuming you need to mount the drive as part of the reboot.  Of
> course you can boot fast with any file system if you don't have to mount
> it.  :-)

Sorry, poor explanation.

Background fsck (when implemented) would operate on a currently mounted
(and active) file system.  The only reason fsck is required prior to
reboot now is because no-one had done the work.

http://www.freebsd.org/cgi/man.cgi?query=fsck&sektion=8&manpath=FreeBSD+5.0-current

See the first paragraph of the above.
-- 
  Rod Taylor