Re: xfs vs jfs performance
There is no question, XFS and JFS have better perf than ext3. However,
in your particular problem, i would look at the FS performances as a
last resort. What about the general IO of this box ? (hdd quality , bus
speed , etc..etc..). Againm 500 files operations a minute does not
sounds to me as a real big load (if it was a second then yes ;), so the
only thing i'm saying is that the problem may be somewhere else.
JeF
On Wed, 2003-02-12 at 08:57, Thedore Knab wrote:
> I am not talking about huge delays but rather occasional 2-5 second delays.
>
> I am using Courier IMAP with the Ext3 file-system and kernel quotas.
>
> Postfix is delivering the Maildir file to the users' space.
>
> The way Courier IMAP works is each mail becomes a separate '.imap' file.
>
> Depending on the file's state, it goes into a different directory.
>
> For example, when a new mail comes in it goes to, Maildir/.new
>
> When it has been viewed it moves from Maildir/.new to Maildir/.cur.
>
> If I put files in my personal directory they end up in
> Maildir/.Personal/.cur.
>
> Since I have about 200 - 250 people logged in during peak periods on a
> dual 700Mhz machine that is mostly idle 95% of the time (except for
> the off peak hour backups and quota indexing), it appears that
> the file-system must be the bottleneck.
>
> I calculate that Courier IMAP is moving about 200-500 files every minute
> during the delays.
>
> Additionally, mail is coming in at the rate of 100-300 messages per minute.
>
> Since ext3 is built on top of ext2, it adds a lot of overhead.
>
> The kernel quotas add more overhead.
>
> Although it is easy to move from ext2 to ext3, it does not offer
> any greater read or write performance.
>
> In this month's Linux Journal, for example,
> there is an article about the new SGI 64 bit machine. One thing that they used for
> metrics was the file-system. According the article both ext2 and xfs
> performed about the same on the 'super server'. Reiser and ext3 both performed
> about 1/4 that of ext2.
>
> Since the system is not being taxed in any other noticeable way
> according to sar, I feel that the file-system must be the bottleneck.
> More specifically, it has to be ext3 or the quotas with ext3.
>
> > On Wed, Feb 12, 2003 at 08:16:47AM +1100, Jean-Francois Dive wrote:
> > Hi,
>
> > not that i ever tested any of those 2 new file-system, but i have some
> > troubles to believe that the FS'd be the bottleneck in your scenario;
> > maybe i'm wrong, and 'd be interested to read some tests too though.
> > JeF
>
>
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--
-> Jean-Francois Dive
--> jef@linuxbe.org
There is no such thing as randomness. Only order of infinite
complexity. - Marquis de LaPlace - deterministic Principles -
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