Re: FreeBSD Softupdates?? - Mailing list pgsql-general

From Alfred Perlstein
Subject Re: FreeBSD Softupdates??
Date
Msg-id 20000926083808.V9141@fw.wintelcom.net
Whole thread Raw
In response to Re: FreeBSD Softupdates??  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: FreeBSD Softupdates??  (Alfred Perlstein <bright@wintelcom.net>)
List pgsql-general
* Bruce Momjian <pgman@candle.pha.pa.us> [000926 07:12] wrote:
> -- Start of PGP signed section.
> > On Tue, Sep 26, 2000 at 03:20:31AM -0700, Alfred Perlstein wrote:
> > > It can cause problems because softupdates makes meta data changes
> > > (in this case file creation/removal) asyncronously, the same actually
> > > happens with most other logging filesystems that don't support
> > > transactions.
> >
> > I've been running FreeBSD 4.1 with soft updates on my development box
> > for a while now without any problems at all. Although it's not
> > production so there's not a lot of load on PgSQL.
> >
> > I don't know if it hurts or hampers performance.
>
> Good question.  I can see soft updates improving performance because it
> flushes meta-data writes all at once, rather than each time a file is
> created/destroyed.  I don't see any downside for PostgreSQL.  The
> default fsync() will still work, or at least it should.  This is not the
> same as mounting a volume as async.

You are correct, softupdates will honour a fsync and stabilize the
file (make sure it's a round if you have a crash).

--
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."

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