Messages in this thread | | | Date | Fri, 03 Sep 2004 21:58:21 +0000 | From | "J.A. Magallon" <> | Subject | Re: md RAID over SATA performance |
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On 2004.09.03, 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: > >
Thanks to everybody for its answers...
My confusion/problem was that I has always tried with only two drives, and with more or less old drives that gave around 20-25Mb/s each, so the raid worked very optimally at about 50 Mb/s. But with modern drives at 55 Mb/s, I hit the PCI speed limits, I suppose. Board is a Supermicro P3TDDE, Via ApolloPro 266T chipset (aghhh), 33 MHz PCI, 2xPIII@933.
With a stock 2.6.8.1, I get this:
nada:~# hdparm -tT /dev/md0
/dev/md0: Timing buffer-cache reads: 864 MB in 2.00 seconds = 431.63 MB/sec Timing buffered disk reads: 252 MB in 3.01 seconds = 83.85 MB/sec
with this setup:
nada:~# mdadm --detail /dev/md0 /dev/md0: Version : 00.90.01 Creation Time : Fri Sep 3 02:17:28 2004 Raid Level : raid5 Array Size : 1225557760 (1168.78 GiB 1254.97 GB) Device Size : 245111552 (233.76 GiB 250.99 GB) Raid Devices : 6 Total Devices : 6 Preferred Minor : 0 Persistence : Superblock is persistent
Update Time : Fri Sep 3 19:01:39 2004 State : clean Active Devices : 6 Working Devices : 6 Failed Devices : 0 Spare Devices : 0
Layout : left-symmetric Chunk Size : 256K
UUID : fd6fcad0:21da140b:072a82b1:11b3db21 Events : 0.239
Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 2 8 33 2 active sync /dev/sdc1 3 8 49 3 active sync /dev/sdd1 4 8 65 4 active sync /dev/sde1 5 8 81 5 active sync /dev/sdf1
-- J.A. Magallon <jamagallon()able!es> \ Software is like sex: werewolf!able!es \ It's better when it's free Mandrakelinux release 10.1 (RC 1) for i586 Linux 2.6.8.1-mm4 (gcc 3.4.1 (Mandrakelinux (Alpha 3.4.1-3mdk)) #8
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