From: Brad Campbell <brad@wasp.net.au>
To: "J.A. Magallon" <jamagallon@able.es>
Cc: Lista Linux-Kernel <linux-kernel@vger.kernel.org>,
Jeff Garzik <jgarzik@pobox.com>
Subject: Re: md RAID over SATA performance
Date: Fri, 03 Sep 2004 17:24:01 +0400 [thread overview]
Message-ID: <41387071.4010504@wasp.net.au> (raw)
In-Reply-To: <1094169937l.17931l.0l@werewolf.able.es>
J.A. Magallon wrote:
> Hi all...
>
> I am buildin an array with a linux box, and I run 2.6.8.1 (not stock, but
> the mandrake cooker version).
>
> Disks are 6 SATA drives, plugged to a couple of Promise FastTrak S150 TX4
> cards.
>
> Problem is that i get really poor performance. A single drive gives about
> 57 Mb/s, and a raid1 with two just gives about 64 Mb/s (measured with
> hdparm -tT). With the six drives:
>
> nada:~/soft/kernel# hdparm -tT /dev/sda
>
> /dev/sda:
> Timing buffer-cache reads: 844 MB in 2.01 seconds = 419.96 MB/sec
> Timing buffered disk reads: 174 MB in 3.01 seconds = 57.84 MB/sec
> nada:~/soft/kernel# hdparm -tT /dev/md0
>
> /dev/md0:
> Timing buffer-cache reads: 884 MB in 2.00 seconds = 441.63 MB/sec
> Timing buffered disk reads: 310 MB in 3.01 seconds = 103.07 MB/sec
>
> The real goal is to build a raid5 system, but I just tested with raid1.
>
Here are some real-world figures for you (Not that they mean anything!)
srv:/home/brad# hdparm -t -T /dev/md0
/dev/md0:
Timing buffer-cache reads: 1340 MB in 2.00 seconds = 668.76 MB/sec
BLKGETSIZE failed: File too large
Timing buffered disk reads: 182 MB in 3.02 seconds = 60.31 MB/sec
srv:/home/brad# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda1 19G 11G 6.5G 64% /
tmpfs 252M 0 252M 0% /dev/shm
/dev/hda3 165G 21G 136G 13% /raid0
/dev/md0 2.1T 2.0T 114G 95% /raid
/dev/md2 459G 101G 358G 22% /raid2
srv:/home/brad# mdadm --detail /dev/md0
/dev/md0:
Version : 00.90.01
Creation Time : Sun May 2 18:02:14 2004
Raid Level : raid5
Array Size : 2206003968 (2103.81 GiB 2258.95 GB)
Device Size : 245111552 (233.76 GiB 250.99 GB)
Raid Devices : 10
Total Devices : 10
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Fri Sep 3 16:08:03 2004
State : clean, no-errors
Active Devices : 10
Working Devices : 10
Failed Devices : 0
Spare Devices : 0
Layout : left-asymmetric
Chunk Size : 128K
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/devfs/scsi/host0/bus0/target0/lun0/part1
1 8 17 1 active sync /dev/devfs/scsi/host1/bus0/target0/lun0/part1
2 8 33 2 active sync /dev/devfs/scsi/host2/bus0/target0/lun0/part1
3 8 49 3 active sync /dev/devfs/scsi/host3/bus0/target0/lun0/part1
4 8 65 4 active sync /dev/devfs/scsi/host4/bus0/target0/lun0/part1
5 8 81 5 active sync /dev/devfs/scsi/host5/bus0/target0/lun0/part1
6 8 97 6 active sync /dev/devfs/scsi/host6/bus0/target0/lun0/part1
7 8 113 7 active sync /dev/devfs/scsi/host7/bus0/target0/lun0/part1
8 8 129 8 active sync /dev/sdi1
9 8 145 9 active sync /dev/sdj1
UUID : 05cc3f43:de1ecfa4:83a51293:78015f1e
Events : 0.681631
next prev parent reply other threads:[~2004-09-03 13:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-03 0:05 md RAID over SATA performance J.A. Magallon
2004-09-03 0:47 ` J.A. Magallon
2004-09-03 8:09 ` David Greaves
2004-09-03 16:15 ` Mark Lord
2004-09-03 11:13 ` Alan Cox
2004-09-03 13:24 ` Brad Campbell [this message]
2004-09-03 16:33 ` Mark Lord
2004-09-03 20:27 ` Tomasz Torcz
2004-09-04 13:38 ` Mark Lord
2004-09-03 21:58 ` J.A. Magallon
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