Re: md RAID over SATA performance

From: J.A. Magallon
Date: Thu Sep 02 2004 - 19:59:04 EST



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
^^^^^
OOPS, I meant raid0...
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.

Any ideas/suggestions ?

TIA

More info:

nada:~/soft/kernel# mdadm --detail /dev/md0
/dev/md0:
Version : 00.90.01
Creation Time : Fri Sep 3 01:52:22 2004
Raid Level : raid0
Array Size : 1470669312 (1402.54 GiB 1505.97 GB)
Raid Devices : 6
Total Devices : 6
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Fri Sep 3 01:52:22 2004
State : clean
Active Devices : 6
Working Devices : 6
Failed Devices : 0
Spare Devices : 0

Chunk Size : 128K

UUID : c7373f10:3d04436b:a7d2bbce:8317b56f
Events : 0.14

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

nada:~/soft/kernel# lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT8633 [Apollo Pro266] (rev 01)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8633 [Apollo Pro266 AGP]
00:07.0 RAID bus controller: Promise Technology, Inc. PDC20319 (FastTrak S150 TX4) (rev 02)
00:08.0 RAID bus controller: Promise Technology, Inc. PDC20319 (FastTrak S150 TX4) (rev 02)
00:0b.0 Multimedia audio controller: Ensoniq 5880 AudioPCI (rev 02)
00:0c.0 RAID bus controller: Promise Technology, Inc. PDC20267 (FastTrak100/Ultra100) (rev 02)
00:0d.0 Ethernet controller: Intel Corp. 82557/8/9 [Ethernet Pro 100] (rev 08)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8233 PCI to ISA Bridge
00:11.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:11.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 1b)
00:11.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 1b)
00:11.4 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 1b)
00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II] (rev 62)
01:00.0 VGA compatible controller: nVidia Corporation NV11 [GeForce2 MX/MX 400] (rev b2)



--
J.A. Magallon <jamagallon()able!es> \ Software is like sex:
werewolf!able!es \ It's better when it's free
Mandrakelinux release 10.1 (Beta 1) for i586
Linux 2.6.8.1-mm4 (gcc 3.4.1 (Mandrakelinux (Alpha 3.4.1-3mdk)) #8


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