From: "Eric D. Mudama" <edmudama@mail.bounceswoosh.org>
To: Willy Tarreau <willy@w.ods.org>
Cc: Timothy Miller <miller@techsource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: File system performance, hardware performance, ext3, 3ware RAID1, etc.
Date: Fri, 13 Feb 2004 12:30:46 -0700 [thread overview]
Message-ID: <20040213193046.GA17790@bounceswoosh.org> (raw)
In-Reply-To: <20040213055350.GG29363@alpha.home.local>
On Fri, Feb 13 at 6:53, Willy Tarreau wrote:
>It depends on the disk too. Lots of disks (specially IDE) are far slower
>on writes than they are on reads.
This may be a function of the operating system or the filesystem, but
it isn't necessarilly an artifact of the drives themselves. With both
read and write caching enabled, random writes will always be faster
than random reads from the drive perspective.
Even with queueing enabled (legacy TCQ or Native-SATA "NCQ"), your
ability to reorder reads is limited in ATA to 32 tags, while the
ability to reorder cached writes is limited only by buffer size and
cache granularity... the absolute worst-case write performance should
be the same as read performance.
--eric
--
Eric D. Mudama
edmudama@mail.bounceswoosh.org
next prev parent reply other threads:[~2004-02-13 19:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-12 23:32 Timothy Miller
2004-02-13 5:53 ` Willy Tarreau
2004-02-13 19:19 ` Timothy Miller
2004-02-13 22:39 ` Willy Tarreau
2004-02-13 23:14 ` Timothy Miller
2004-02-13 19:30 ` Eric D. Mudama [this message]
2004-02-13 19:55 ` Linus Torvalds
2004-02-13 20:44 ` John Bradford
2004-02-13 22:45 ` Willy Tarreau
2004-02-13 12:23 Daniel Blueman
2004-02-13 14:27 ` Jamie Lokier
2004-02-13 14:44 ` Daniel Blueman
2004-02-13 16:15 ` Bartlomiej Zolnierkiewicz
2004-02-13 22:56 ` Timothy Miller
2004-02-14 18:16 Walt H
2004-02-16 17:53 ` Timothy Miller
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