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9739
April 8th, 2008 23:00
MD3000i performance metrics
Hi All,
We have had a MD3000i for awhile now and are trying to get the most out of the performance of the unit, unfortunately I am not sure what performance to expect from the unit so I keep thinking that it is slow.
We have tried multiple configs starting with 5 disk raid 5, 14 disk raid 5, 7 disk raid 0, 14 disk raid 0, 14 disk raid 10, 6 disk raid 10, both in 128K and 256K stripes. I have always gotten the same results from the unit (The unit originally came with 15X750GB 7.2K sata drives, Dell has graciously loaned us 15X300GB 15K sas to test with) with sata or sas. I have tried 2 performance monitoring tools HD Tach (probably not the greatest), Hd Tune Pro (Better, 64K Block Size), I am going to try IO meter if anyone has any suggestions for max Disk Size, Starting Disk Sector, # outstanding Io and Connection Rate. Anyway with the two tools I seem to have a transfer rate in the low 50MB/Sec and the High 60MB/sec and it does not matter what raid level or how many drives that it happens to be striped on. We have tested the connection on 3 servers a 2950 with a quad core and a dedicated PCIE dual port card, two 2650's one with a Intel Pro 1000T PCI-X card and the other running with internal Broadcom's. I have set up all units according to the document at http://www.delltechcenter.com/page/MPIO+to+PowerVault+MD3000i+with+Microsoft+iSCSI+Initiator
as well as aligned the file system with the document
(http://technet.microsoft.com/en-us/library/aa995867.aspx <http://technet.microsoft.com/en-us/library/aa995867.aspx> ) from Microsoft.
The MD3000i has two controllers and is setup with two subnets hooked into two 5424 DELL switches with Jumbo frames enabled. Jumbo Frames are enabled on the MD3000i and the client as well. Is there something that I am missing? If anyone else has run some performance monitoring with either of the above tools it would be great to do some comparisons.
I see people and reviews stating that they have seen over 100MB/sec on these units? Is this indeed possible?
Any suggestions are welcome.
Thanks,
M_S
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dzenz
175 Posts
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April 11th, 2008 01:00
The MD3000i is capable of Gigabit line rates, however what's really most important is to understand the usage and intended applications. The two HD tools mentioned are not used to characterize enterprise storage. Iometer is however the profile has to be tuned to match the intended application.
What are the applications that you would like to use with the MD3000i?
Dave
Master_Sorcerer
4 Posts
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April 11th, 2008 02:00
We were initially looking for some near line storage since we have a MD1000 hooked into out backup unit (A 2950) with a Perc 5E. It is starting to get to capacity, we wanted to transfer the data off of the 750 SATA drives on the MD1000 to the MD3000i and then attach the MD1000 to the MD3000i. We found that transferring the Data was way too slow and the backup times off of the nearline storage to tape would take quite a bit more time than they are currently. We also wanted to use the unit for archiving email with quest software email archive, since the IO on the systems would be being used at different times throughout the day we thought this would be a perfect fit. I am not concerned about the near line storage we will purchase another MD1000 if we have too, but I am concerned about performance with the quest archive tools. This is why we had Dell ship us 15x300 15K drives to test with.
Thanks,
M_S
Dev Mgr
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April 11th, 2008 13:00
The MD3000/3000i can only make virtual disks up to 2036GB each. As I assume your using the Microsoft iSCSI initiator you cannot use dynamic disks.
If you're running out of space on your MD1000 I assume you have several TBs in a single virtual disk and then use GPT to make it one large partition.
With the MD3000 series you cannot do this and as you're wanting the iSCSI version you cannot use dynamic disk to span it together either.
If you need very large storage that can look like a single disk in the OS, consider looking at Dell's AX4-5i with the full version of Navisphere Manager. This system doesn't have the 2TB cap like the MD3000/3000i and the full version allows you to span virtual disks together to make the OS see it as a single (very) large disk.