Slow SCSI disk axx

linkmark · 05-07-2007, 10:41 AM

Hi all.

Can someone tell me how to speed up my disk preformance.
I have a Fujitsu Siemens PRIMERGY N200 with the following hardisk config:

2x Seagate ST336704LC Cheetah 36.7GB 10,000RPM 80-Pin Ultra160 SCSI Wide Hard Drive
http://www.netcomdirect.com/sestch361080.html

With a PCI Adaptec I2O 2100S (32MB) RAID controller
http://www.adaptec.com/en-US/support...aid/ASR-2100S/

The 2 disks are in mirror RAID 1, is working smooth.

I have all the kernel hardware drivers that i could find for that server, compiled into my kernel (IDE controller, RAID controller, NIC, ..).

I did a hdparm test on the RAID disk sda:
N200 ~ # hdparm -Tt /dev/sda

/dev/sda:
Timing cached reads: 764 MB in 2.01 seconds = 380.28 MB/sec
Timing buffered disk reads: 8 MB in 3.18 seconds = 2.51 MB/sec

So is there anything I can do / try, besides tweaking with hdparm? I have 2 other Gentoo machines, with normal IDE disks, and they run a lot faster than my SCSI's (wich schould run faster then my IDEs, right?).

Thanks in advanced !!
Linkmark

rtspitz · 05-07-2007, 04:20 PM

just about 400MB/s cached reads ?
that is rather slow.

if your scsi controller has a bios, what kind of transfer mode is selected ?
async, sync, wide ?

linkmark · 05-08-2007, 11:41 AM

Quote:

Originally Posted by rtspitz

just about 400MB/s cached reads ?
that is rather slow.

if your scsi controller has a bios, what kind of transfer mode is selected ?
async, sync, wide ?

Yeah it's very slow.
Transfer mode selected for BUS 0 is Ultra160, and they are async

Searched google like hell, can't find anything to fix this

rtspitz · 05-08-2007, 12:11 PM

async ? that might be the culprit.

I once had that problem with an LSI controller (HP server + HP modified lsi bios). It suddenly would not use sync transfer and speeds dropped to almost zero. Had to return said controller. With our current adaptec card those settings can be set in the bios (maybe "domain validation" needs to be forced / turned off).

here are some numbers for reference:

- HP DL385 (dual opteron, 2GB, Adaptec ASC-39320A U320, external raid appliance):

Code:

Timing cached reads:   3852 MB in  2.00 seconds = 1927.06 MB/sec
Timing buffered disk reads:  196 MB in  3.03 seconds =  64.70 MB/sec

linkmark · 05-08-2007, 05:25 PM

Quote:

Originally Posted by rtspitz

async ? that might be the culprit.

I once had that problem with an LSI controller (HP server + HP modified lsi bios). It suddenly would not use sync transfer and speeds dropped to almost zero. Had to return said controller. With our current adaptec card those settings can be set in the bios (maybe "domain validation" needs to be forced / turned off).

here are some numbers for reference:

- HP DL385 (dual opteron, 2GB, Adaptec ASC-39320A U320, external raid appliance):

Code:

Timing cached reads:   3852 MB in  2.00 seconds = 1927.06 MB/sec
Timing buffered disk reads:  196 MB in  3.03 seconds =  64.70 MB/sec

Great, I'll look into that async thing.

But I try to use my onboard raid controller, some guy on irc told me to try that and test the speed. Only a bit faster. But now my second hard disk, so the one in mirror, is failing. Have to figure that out first.

Thanks man !
Regards