From: david@lang.hm
To: Tejun Heo <htejun@gmail.com>
Cc: David Chinner <dgc@sgi.com>,
linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org,
device-mapper development <dm-devel@redhat.com>,
Jens Axboe <jens.axboe@oracle.com>,
linux-fsdevel@vger.kernel.org,
Andreas Dilger <adilger@clusterfs.com>
Subject: Re: Re: [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md.
Date: Thu, 31 May 2007 22:55:58 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0705312144400.6705@asgard.lang.hm> (raw)
In-Reply-To: <465F9197.7060002@gmail.com>
On Fri, 1 Jun 2007, Tejun Heo wrote:
> but one
> thing we should bear in mind is that harddisks don't have humongous
> caches or very smart controller / instruction set. No matter how
> relaxed interface the block layer provides, in the end, it just has to
> issue whole-sale FLUSH CACHE on the device to guarantee data ordering on
> the media.
if you are talking about individual drives you may be right for the moment
(but 16M cache on drives is a _lot_ larger then people imagined would be
there a few years ago)
but when you consider the self-contained disk arrays it's an entirely
different story. you can easily have a few gig of cache and a complete OS
pretending to be a single drive as far as you are concerned.
and the price of such devices is plummeting (in large part thanks to Linux
moving into this space), you can now readily buy a 10TB array for $10k
that looks like a single drive.
David Lang
next prev parent reply other threads:[~2007-06-01 5:55 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-25 7:58 [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md Neil Brown
2007-05-25 11:15 ` David Chinner
2007-05-25 11:49 ` Jens Axboe
2007-05-25 14:49 ` Phillip Susi
2007-05-28 18:32 ` [dm-devel] " Jens Axboe
2007-05-25 13:52 ` Stefan Bader
2007-05-28 1:37 ` Neil Brown
2007-05-29 9:12 ` Stefan Bader
2007-05-25 15:11 ` Phillip Susi
2007-05-26 1:03 ` Andreas Dilger
2007-05-26 10:27 ` Tejun Heo
2007-05-28 1:30 ` Neil Brown
2007-05-28 2:45 ` David Chinner
2007-05-28 2:57 ` Neil Brown
2007-05-28 4:29 ` David Chinner
2007-05-31 0:46 ` Neil Brown
2007-05-31 0:57 ` Alasdair G Kergon
2007-05-31 1:07 ` Alasdair G Kergon
2007-05-31 1:11 ` David Chinner
2007-05-28 4:48 ` Timothy Shimmin
2007-05-29 6:45 ` Jeremy Higdon
2007-05-29 20:03 ` Phillip Susi
2007-05-29 23:48 ` David Chinner
2007-05-30 0:01 ` david
2007-05-30 6:17 ` David Chinner
2007-05-30 8:55 ` Stefan Bader
2007-05-30 16:52 ` david
2007-05-31 0:20 ` David Chinner
2007-05-31 6:26 ` Jens Axboe
2007-05-31 7:03 ` David Chinner
2007-05-31 7:06 ` Jens Axboe
2007-05-31 13:30 ` Bill Davidsen
2007-05-31 13:36 ` Jens Axboe
2007-06-01 16:04 ` Bill Davidsen
2007-06-02 14:51 ` Jens Axboe
2007-06-02 19:55 ` Bill Davidsen
2007-06-01 3:16 ` Tejun Heo
2007-06-01 8:21 ` Jens Axboe
2007-06-02 9:20 ` Tejun Heo
2007-06-02 14:34 ` Jens Axboe
2007-06-02 22:57 ` Guy Watkins
2007-06-04 7:39 ` Tejun Heo
2007-05-31 18:31 ` Phillip Susi
2007-05-31 19:00 ` Jens Axboe
2007-05-31 19:21 ` david
2007-05-31 19:40 ` Jens Axboe
2007-05-31 23:34 ` David Chinner
2007-06-01 5:59 ` Neil Brown
2007-06-01 6:11 ` Jens Axboe
2007-06-01 7:53 ` David Chinner
2007-06-01 23:56 ` Bill Davidsen
2007-05-31 18:24 ` Phillip Susi
2007-05-30 16:45 ` Phillip Susi
2007-05-30 20:27 ` [dm-devel] " Phillip Susi
2007-05-31 6:24 ` Jens Axboe
2007-05-31 18:37 ` [dm-devel] " Phillip Susi
2007-05-31 18:58 ` Jens Axboe
2007-06-02 0:04 ` Bill Davidsen
2007-05-28 9:29 ` Tejun Heo
2007-05-28 9:43 ` Alasdair G Kergon
2007-05-29 9:25 ` [dm-devel] " Stefan Bader
2007-05-29 22:05 ` Alasdair G Kergon
2007-05-30 9:12 ` [dm-devel] " Stefan Bader
2007-05-30 10:41 ` Alasdair G Kergon
2007-05-30 16:55 ` Phillip Susi
2007-05-31 11:14 ` [dm-devel] " Stefan Bader
2007-06-01 3:25 ` Tejun Heo
2007-06-01 5:55 ` david [this message]
2007-06-01 7:16 ` [dm-devel] " Tejun Heo
2007-06-01 17:07 ` Valdis.Kletnieks
2007-06-01 18:09 ` Tejun Heo
2007-07-10 18:39 ` Ric Wheeler
2007-07-10 23:40 ` Valdis.Kletnieks
2007-07-11 2:49 ` Tejun Heo
2007-07-11 22:44 ` Ric Wheeler
2007-07-12 17:34 ` Valdis.Kletnieks
2007-07-12 19:43 ` Ric Wheeler
2007-07-12 23:10 ` Guy Watkins
2007-07-13 11:30 ` Ric Wheeler
2007-07-11 2:51 ` Tejun Heo
2007-05-29 19:59 ` Phillip Susi
2007-05-31 0:22 ` Neil Brown
2007-05-30 9:35 ` Jens Axboe
2007-07-05 12:28 ` Tejun Heo
2007-07-09 12:27 ` Jens Axboe
2007-07-18 10:56 ` [PATCH] block: cosmetic changes Tejun Heo
2007-07-18 10:59 ` [PATCH] block: factor out bio_check_eod() Tejun Heo
2007-07-18 11:06 ` Jens Axboe
2007-07-18 11:18 ` Tejun Heo
2007-07-18 11:31 ` Jens Axboe
2007-07-18 11:33 ` Tejun Heo
2007-07-18 11:34 ` Jens Axboe
2007-07-18 11:41 ` Tejun Heo
2007-07-18 11:45 ` Jens Axboe
2007-07-18 11:49 ` Jens Axboe
2007-07-18 12:34 ` Tejun Heo
2007-07-18 12:31 ` Jens Axboe
2007-05-28 11:17 ` [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md Nikita Danilov
2007-05-31 3:31 ` Neil Brown
2007-05-28 14:43 ` Bill Davidsen
2007-05-31 0:37 ` Neil Brown
2007-05-31 12:28 ` Bill Davidsen
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