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Video Editing SAN Advice

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MattWright2001

Technical User
Jan 16, 2009
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Hi There, I am new to this forum, and a bit of a newb to the world of SAN's. so please be gentle

Anyway here is what I am trying to do, we have 3 editors who are using a SAN.

We have a Xyratex 5402E Raid Enclosure loaded with 12 x 500GB SATA Drives, the enclosure has 2 Fiber Channel Controllers, which in turn are both connected to a QLogic 4GB Switch. and then we have 3 XP64 computers connected via FC to the Qlogic switch at 4GB.

The 12 drives are configured currently as 2 banks of RAID 5, so we have 6 drives Raided together as a Raid 5, and the other 6 also raided together as a Raid 5.

Then in windows XP we Raid 0 the 2 partitions back together to create a single shared resource. We are using MetaSAN software on the 3 systems to access the drives giving us file level sharing.

So my problem, It just seems really slow, I can get a maximum Read / Write of about 225MB/s Read and 150MB/s Write, which isn't too bad I guess, but I would expect it to be a bit quicker, and also we get pauses and inconsistency's with the data rate. The data rate will just plummet down to about 20MB/s Read and Write for a second then fire back upto full speed, which to be honest is crap if you are trying to edit HD streams.

I think the problem is basically down to Block Size settings in the Raid Configuration, Cache Settings in the Raid software, sector size settings in Windows, and also which Raid partition is accessible through which Fiber Controller on the Xyratex COntroller. and unfortunately this has so may variables I am not sure where to start to try and improve the situation.

So my question to SAN Masters, is HELP !!!!, well, lets say do you have any advice to get my speeds up and more consistent.

Many Thanks for this

Matt







 
Why do stripe across two raid 5 sets in software versus having a larger raid 5? It seems like there is a lot of overhead for doing that along with sharing the lun with 3 machines.
 
We did also have a 32bit xp system attached to the raid as well. And so it would complain of a single Lun over 2TB. So to make a larger drive we formatted it that way. We were also told because of the 2 controllers it was the way to do it. I guess we could run gpt formatted drives and run a single raid. Do you think that would be safer / quicker. Also can an xp32 system see
A gpt formatted drive over a network?
Thx matt
 
It seems like it would be quicker because you wouldn't be running a software raid. Just make sure your controller supports a LUN > 2tb if that is the case. GPT partition should be fine for WinXP.
 
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