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MD3600f 36 Disks RAID10 slow perfomance
Hello, all!
I configured MD3600 storage as single virtual disk. (RAID10 36x3TB nearline SAS) for use as shared storage for Citrix Xenserver 6.0.2.
I did not expect such a poor performance.
root@SG-DebStor1:/srv/stor# dd if=/dev/zero of=temp.file bs=1M count=9000
9000+0 records in
9000+0 records out
9437184000 bytes (9.4 GB) copied, 109.487 s, 86.2 MB/s
I have a newest firmware update, but it doesnt helps.
Maybe someone else have a similar configuration, and suggest what should be the performance?
Sorry about my English.
HBA Controllers is Qlogic 8 Gb/s QME2572, cabeling is made in accordance with manual.
Cabeling Scheme:
https://picasaweb.google.com/lh/photo/W_joTD4fmyLFsVplXQo5AFbCu2p-vEvn-z_IBw-gWn0?feat=directlink
Zoning of Brocade Switches is configured properly (single initiator with all targets).
Multipathing is enabled:
https://picasaweb.google.com/lh/photo/Fve8KbFXYy8qsHcsRIQfaFbCu2p-vEvn-z_IBw-gWn0?feat=directlink
The connections were checked Dell Support.
DELL-Kenny K
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Posted March 27th, 2012 10:00
It looks like that the only XenServer 5.6.0 is supported on the 3600f so we do not have any documents that explains what will need to be done since it is a unsupported config. However, There are a couple things that you could try that may be helpful to you.
1. You might try through sansurfer CLI to try and adjust the linux qlport_down_retry count to 10 from the default settings.
2. You may also want to adjust the multipath mode to Round Robin.
I hope this helps.
When you formatted the VD for zen, did you do a full format or quick. Roughly 56tb of nearline disks in one VD would take a couple of days to format. If it was a quick format then that will introduce a performance hit as each write operation takes 3 disk operations. format, write and verify. I don't know if that equates to your figures just that External/SAN storage VD's should be full formatted before use.
No, I dont have high-perfomance tier license.
It seems that the performance is reduced in proportion to the number of virtual machines running on the shared storage, and number of virtual machines running on same host.
Migration guest vm to host without running VMs increases dd perfomance twice!
DELL-Kenny K
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Posted March 27th, 2012 09:00
What controllers are in the server that the SAN is connected to? Also how is it currently cabled together? With the info that you have provided it is still hard to tell exactly what could be causing the performance issue. Below is a couple of links that should assist you in making sure the MD3600f if set up properly. The first link is for the MD3600f Deployment Guide and the second link is info on configuring Fibre Channel with MD3600f.
support.dell.com/.../DG.pdf
support.dell.com/.../ConfigFC.pdf
If you have any kind of questions or concerns while going through this material. Please let me know as I would be happy to assist you.