performance problem with amr driver and Perc 2/SC
Jesse Guardiani
jesse at wingnet.net
Thu Nov 6 05:20:29 PST 2003
Howdy list,
I have a 500Mhz Dell PowerEdge 4300 with:
[7:22]jesse at chortos:[~]# uname -a
FreeBSD chortos.wingnet.net 4.8-RELEASE FreeBSD 4.8-RELEASE #0: Fri Apr 11 12:59:08 EDT 2003 jesse at chortos.wingnet.net:/usr/src/sys/compile/CHORTOS i386
[7:42]jesse at chortos:[~]# grep amr /var/run/dmesg.boot
amr0: <LSILogic MegaRAID> mem 0xf4c00000-0xf4ffffff irq 10 at device 13.1 on pci2
amr0: <Series 466> Firmware 3.00, BIOS 1.36, 16MB RAM
amrd0: <LSILogic MegaRAID logical drive> on amr0
amrd0: 51834MB (106156032 sectors) RAID 5 (optimal)
And I think I'm having performance problems. I am running a
RAID 5 array with 5 18 Gb SCSI disks.
The disks have varying speeds and capabilities:
-------------------------------------------------------
Slot SCSI ID Model # or Serial Brand/Model Specs
---- ------- ----------------- ----------- -----
0 (orig) 0 DNES-318350 E182115 S IBM Ultra 3 SCSI Wide (80 MB/Sec)
P/N: 25L2142 18.2 GB
7,200 RPM
1 (orig) 1 DNES-318350 E182115 S IBM Ultra 3 SCSI Wide (80 MB/Sec)
P/N: 25L2142 18.2 GB
7,200 RPM
2 2 ST318203LC Seagate/Cheetah Ultra 2 SCSI Wide (80 MB/Sec)
18.21 GB (5.4ms seek time)
10,000 RPM
3 3 Dell P/N: Quantum/Atlas 10K Ultra 3 SCSI (160 MB/Sec)
JP-082YPV-12541-03R-00MB 18.2 GB
TN18J462 10,000 RPM
4 4 --BLANK--
5 (hotsp) 5 PN34L7404 IBM Ultra 3 SCSI (160 MB/Sec)
ECF24486 18 GB
7,200 RPM
8 8 --BLANK--
9 9 --BLANK--
-------------------------------------------------------
The problem is that this box is averaging the following,
according to tests with dd:
write read
2.05 MByte/Sec 12.59 MByte/Sec
Here are the exact tests I run:
write test:
sh -c 'time -h dd if=/dev/zero bs=1024k of=tstfile count=1024'
read test:
sh -c 'time -h dd if=tstfile bs=1024k of=/dev/null'
Each test is run seperately. I monitor CPU usage via top
in a seperate terminal and monitor `iostat -w 1` in yet
another terminal.
Here is the result of the write test:
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 498.681822 secs (2153160 bytes/sec)
8m19.03s real 0.01s user 17.41s sys
CPU varied during this test, but I'd guess that I averaged
50% idle or more. This is typically what the dd process looked
like in top:
45270 root -18 0 2268K 1128K wdrain 0:03 3.16% 3.03% dd
Here is some of the iostat output I get during the write
test:
-------------------------------------------------------
tty amrd0 cd0 sa0 cpu
tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
0 227 60.05 41 2.38 0.00 0 0.00 0.00 0 0.00 56 0 42 2 0
3 6142 53.31 49 2.53 0.00 0 0.00 0.00 0 0.00 26 0 16 2 57
0 377 71.95 38 2.64 0.00 0 0.00 0.00 0 0.00 1 0 7 2 91
0 369 88.18 34 2.90 0.00 0 0.00 0.00 0 0.00 1 0 5 0 95
0 341 57.42 38 2.11 0.00 0 0.00 0.00 0 0.00 1 0 5 1 93
0 2285 58.48 42 2.37 0.00 0 0.00 0.00 0 0.00 1 0 10 1 88
0 2420 79.33 36 2.76 0.00 0 0.00 0.00 0 0.00 0 0 5 0 95
0 2393 88.24 34 2.89 0.00 0 0.00 0.00 0 0.00 2 0 7 0 92
0 337 58.29 42 2.37 0.00 0 0.00 0.00 0 0.00 4 0 10 0 86
0 354 70.91 35 2.40 0.00 0 0.00 0.00 0 0.00 3 0 6 2 89
0 419 50.91 44 2.17 0.00 0 0.00 0.00 0 0.00 3 0 6 0 91
0 76 39.90 60 2.35 0.00 0 0.00 0.00 0 0.00 12 0 10 0 78
0 1181 60.49 44 2.61 0.00 0 0.00 0.00 0 0.00 19 0 42 2 36
0 76 96.00 31 2.88 0.00 0 0.00 0.00 0 0.00 40 0 49 0 12
0 2629 68.82 39 2.60 0.00 0 0.00 0.00 0 0.00 35 0 13 2 51
0 416 77.73 30 2.25 0.00 0 0.00 0.00 0 0.00 1 0 9 0 91
0 2509 88.77 26 2.23 0.00 0 0.00 0.00 0 0.00 1 0 5 1 94
0 299 35.26 53 1.84 0.00 0 0.00 0.00 0 0.00 0 0 5 1 94
0 2417 27.12 72 1.91 0.00 0 0.00 0.00 0 0.00 4 0 3 0 93
0 2463 22.20 81 1.76 0.00 0 0.00 0.00 0 0.00 11 0 14 0 75
-------------------------------------------------------
Any ideas on why I can't throughput more than 3 MB/s?
Does it have anything to do with the fact that my disks
have different RPM speeds?
My 5400 RPM ATA laptop hard drive (~13 MB/Sec Read and Write)
gets better throughput than this RAID 5 array. Something is
very wrong.
--
Jesse Guardiani, Systems Administrator
WingNET Internet Services,
P.O. Box 2605 // Cleveland, TN 37320-2605
423-559-LINK (v) 423-559-5145 (f)
http://www.wingnet.net
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