Xserve Raid speed test at DVinfo.net

Levan Bakhia · August 7th, 2006, 01:24 AM

Can anyone tell me how to test the speed of my XSERVE raid over fiber channel. I am not sure if it performs well.

David Tamés · August 9th, 2006, 02:54 PM

First of all, if you want to run disk performance tests, I suggest the AJA KONA System Test (Version 2) which tests the system under conditions typical with video playback, capture, and editing. Most of the tests don't require an AJA KONA card. You can download the tests from this page on the AJA site: http://www.aja.com/html/support_kona2_swd.html

And while we're on the topic of performace, make sure you read over the documentation that comes with the Xserve RAID, there are several configuration settings you need to set in order to get maximum performance which you will not get with the default settings. I've been happy with the performance of our Xserve RAIDs after reading the documentation and tuning them accordingly.

In a nutshell, you want to enable the drive cache as well as enable the controller write cache. Your Xserve RAID should draw power from a UPS. Another performance tune you can do is set read prefetch to 8 stripes in order to improve sequential read performance (as is often the case with audio and video editing). You should only enabled the drive caches if the Xserve RAID is connected to a UPS. In addition, only enabled the write caches if you have the controller backup batteries installed.

Levan Bakhia · August 10th, 2006, 04:54 AM

David, Many thanks,

I searched internet for the test software for 3 days and here you gave me a link, it really help, because now I checked it and my doubts are right, the speed is around 80mb/s for both read and write.

I have 7 TB xserve raid, and it is configured as raid 5 on both sides. I don't have two raides raided togather, because I was expecting raid 5 to produce around 200mb/s for read and write speed.

So, can you suggest what could be wrong here?

Don Blish · September 27th, 2006, 09:42 PM

The fiberchannel attachment to your XServ is as fast or faster than direct-attached SATA discs. With that in mind, my experience suggests that the write performance you find disappointing may be a function of choosing RAID5.

As a long time IT manager for commercial apps, I blessed the day I met RAID5. My newest machine I built for editing HDV (PPro2.0+Cineform AccessHD). I found I could not reach 100% CPU utilization during long renders with all my disc store as RAID5. Utilization went from 65% to 100% when I configured the second RAID on my motherboard for RAID0 and used that for video only. In tests I found my 4 SATAII drives under RAID5 could read at about 50megabytes per second but write at only 13. The pair under RAID0 does about 60 read or write. Food for thought.

Remember, RAID5 means every block is written or has parity written to two discs. In RAID0 it is written to one disc or another in alternate stripes, boosting throughput.

August 7th, 2006, 01:24 AM	#1
Levan Bakhia Major Player Join Date: Apr 2005 Posts: 230	Xserve Raid speed test Can anyone tell me how to test the speed of my XSERVE raid over fiber channel. I am not sure if it performs well. __________________ ____________ www.sarke.ge ---------------- ____________

August 9th, 2006, 02:54 PM	#2
David Tamés Kino-Eye Join Date: Jul 2005 Location: Boston, MA Posts: 457	First of all, if you want to run disk performance tests, I suggest the AJA KONA System Test (Version 2) which tests the system under conditions typical with video playback, capture, and editing. Most of the tests don't require an AJA KONA card. You can download the tests from this page on the AJA site: http://www.aja.com/html/support_kona2_swd.html And while we're on the topic of performace, make sure you read over the documentation that comes with the Xserve RAID, there are several configuration settings you need to set in order to get maximum performance which you will not get with the default settings. I've been happy with the performance of our Xserve RAIDs after reading the documentation and tuning them accordingly. In a nutshell, you want to enable the drive cache as well as enable the controller write cache. Your Xserve RAID should draw power from a UPS. Another performance tune you can do is set read prefetch to 8 stripes in order to improve sequential read performance (as is often the case with audio and video editing). You should only enabled the drive caches if the Xserve RAID is connected to a UPS. In addition, only enabled the write caches if you have the controller backup batteries installed. __________________ David Tames { blog: http://Kino-Eye.com twitter: @cinemakinoeye }

August 10th, 2006, 04:54 AM	#3
Levan Bakhia Major Player Join Date: Apr 2005 Posts: 230	David, Many thanks, I searched internet for the test software for 3 days and here you gave me a link, it really help, because now I checked it and my doubts are right, the speed is around 80mb/s for both read and write. I have 7 TB xserve raid, and it is configured as raid 5 on both sides. I don't have two raides raided togather, because I was expecting raid 5 to produce around 200mb/s for read and write speed. So, can you suggest what could be wrong here? __________________ ____________ www.sarke.ge ---------------- ____________

September 27th, 2006, 09:42 PM	#4
Don Blish Major Player Join Date: Oct 2003 Location: Portland OR Posts: 227	Throughput: RAID5 vs RAID0 The fiberchannel attachment to your XServ is as fast or faster than direct-attached SATA discs. With that in mind, my experience suggests that the write performance you find disappointing may be a function of choosing RAID5. As a long time IT manager for commercial apps, I blessed the day I met RAID5. My newest machine I built for editing HDV (PPro2.0+Cineform AccessHD). I found I could not reach 100% CPU utilization during long renders with all my disc store as RAID5. Utilization went from 65% to 100% when I configured the second RAID on my motherboard for RAID0 and used that for video only. In tests I found my 4 SATAII drives under RAID5 could read at about 50megabytes per second but write at only 13. The pair under RAID0 does about 60 read or write. Food for thought. Remember, RAID5 means every block is written or has parity written to two discs. In RAID0 it is written to one disc or another in alternate stripes, boosting throughput.