Comments on: Dell SAS 5/i poor performance http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html Notes about *nix, hardware & software, performance & optimization Wed, 07 Jan 2009 12:27:47 +0000 http://wordpress.org/?v=2.1 By: patricko http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-390 patricko Fri, 13 Apr 2007 09:10:49 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-390 After spending weeks isolating, I came to the conclusion that I/O is bad on 1950. But I need confirmation! Googling awhile and you are my confirmation!!! Thanks buddy. After spending weeks isolating, I came to the conclusion that
I/O is bad on 1950. But I need confirmation!

Googling awhile and you are my confirmation!!!

Thanks buddy.

]]> By: patricko http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-391 patricko Fri, 13 Apr 2007 10:52:15 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-391 Call DELL support. The Chap told me to try these setting: And my I/O contention is gone! "We need manually set 'READ AHEAD' & 'WRITE BACK' on your RAID CARD setting." My guess: Last time, older DELL server RAID CARD have hardware cache BUILT into the CARD but NEWER server x290 series USES RAM instead of cache. Call DELL support.

The Chap told me to try these setting:

And my I/O contention is gone!

“We need manually set ‘READ AHEAD’ & ‘WRITE BACK’
on your RAID CARD setting.”

My guess:

Last time, older DELL server RAID CARD have
hardware cache BUILT into the CARD but NEWER
server x290 series USES RAM instead of cache.

]]> By: Klug http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-765 Klug Thu, 17 May 2007 15:41:50 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-765 Same issue here 8-/ There's a brand new firmware (april 17) to download from Dell's website, I did not try it yet. Did you set the "read ahead" and "write back" into BIOS (at boot time) or in your OS driver ? Same issue here 8-/

There’s a brand new firmware (april 17) to download from Dell’s website, I did not try it yet.

Did you set the “read ahead” and “write back” into BIOS (at boot time) or in your OS driver ?

]]> By: Zulus http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-807 Zulus Wed, 23 May 2007 15:40:26 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-807 Klug, probably we are talking about different controllers. SAS5/i even has not any BIOS You are about PERC5/i and with PERC5/i we haven't any problems. Klug, probably we are talking about different controllers.
SAS5/i even has not any BIOS
You are about PERC5/i and with PERC5/i we haven’t any problems.

]]> By: dimitri http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1594 dimitri Tue, 12 Jun 2007 04:24:31 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1594 I have the *exact* same issue except I have a PE860. Basically I've spent 2 days reading up about this issue and I have dell looking into it. I know I have to *enable* write-back cache but there is no place to enable it. Dell Open Manage does not give me the option, neither does the PERC5/iR Bios... I've checked the LSI site - nothing How do you enable write-back caching with this setup? I don't care about power failure, I'm on UPS Firmware Version 00.10.49.00.06.12.02.00 Driver Version 1.24.04.00 Windows 2003 DataCenter X64 dimitri_c at sympatico.ca I have the *exact* same issue except I have a PE860.

Basically I’ve spent 2 days reading up about this issue and I have dell looking into it. I know I have to *enable* write-back cache but there is no place to enable it. Dell Open Manage does not give me the option, neither does the PERC5/iR Bios…

I’ve checked the LSI site - nothing

How do you enable write-back caching with this setup? I don’t care about power failure, I’m on UPS

Firmware Version 00.10.49.00.06.12.02.00
Driver Version 1.24.04.00
Windows 2003 DataCenter X64

dimitri_c at sympatico.ca

]]> By: dimitri http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1595 dimitri Tue, 12 Jun 2007 04:31:35 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1595 Here's some UNIX guys talking about the same issue: http://www.nabble.com/Dell-SAS5-Performance-Issue-tf3474648.html#a9697855 Scott wrote me: " I added a feature to FreeBSD 6 and 7 last week that enables the SATA write cache on all drives directly connected to an MPT-SAS controller. If you want to try this out, you'll need to update your kernel sources and add the following line to /boot/loader.conf: hw.mpt.enable_sata_wc=1 Most people are reporting a significant increase in write performance. " Here’s some UNIX guys talking about the same issue:

http://www.nabble.com/Dell-SAS5-Performance-Issue-tf3474648.html#a9697855

Scott wrote me:

”
I added a feature to FreeBSD 6 and 7 last week that enables the SATA write cache on all drives directly connected to an MPT-SAS controller.
If you want to try this out, you’ll need to update your kernel sources and add the following line to /boot/loader.conf:

hw.mpt.enable_sata_wc=1

Most people are reporting a significant increase in write performance.
“

]]> By: Zulus http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1596 Zulus Tue, 12 Jun 2007 12:15:17 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1596 Dimitri, please note, PERC5/i != SAS 5i ;-) I'm happy with my servers on PERC5/i, probably because almost servers has a lot of reads and no writes. Dimitri, please note, PERC5/i != SAS 5i ;-)
I’m happy with my servers on PERC5/i, probably because almost servers has a lot of reads and no writes.

]]> By: Zulus http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1597 Zulus Tue, 12 Jun 2007 12:16:32 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1597 BTW, thanks for link BTW, thanks for link

]]> By: dimitri http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1598 dimitri Wed, 13 Jun 2007 04:16:08 +0000 http://www.zulustips.com/2007/03/03/dell-sas-5i-poor-performance.html#comment-1598 fyi I fixed the issue today by enabling Write Caching on the VIRTUAL DISK via an older version of Dell's Raid Manager found here: http://www.dellcommunity.com/supportforums/board/message?board.id=pes_hardrive&thread.id=26011 My writes are much faster now but make sure you run your system on UPS if you go with this setup fyi I fixed the issue today by enabling Write Caching on the VIRTUAL DISK via an older version of Dell’s Raid Manager found here:

http://www.dellcommunity.com/supportforums/board/message?board.id=pes_hardrive&thread.id=26011

My writes are much faster now but make sure you run your system on UPS if you go with this setup

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