PE 2800 Performance Problems

Question

I have 3 PowerEdge 2800 servers which are all having performance issues. I am not talking about being ultra picky and expecting to see the full 320MB/s, these things are being out performed by old laptops! The problem seems to be with the array; it can't serve up data fast enough--but why?

All three servers are pretty much maxed out as far as memory and processor and have 6 300GB 10k drives forming a single RAID-5 (about 1,500 MB). They are all running Windows Server 2003 R2 (32-bit). Here is where it gets strange; these servers should be WAY overkill for what we are doing. One is a file server for an office of about 75 people (Word and Excel stuff mainly) and the other two are running DFS Replication for disaster recovery (one at the same location and another in another office).

On all three servers the peek transfer rate we have seen is about 14 MB/s and average is far lower; this holds true for both network requests and backups (which take over a day to run). I have moved our files to an 850 to get better performance (as sad as that is) until we correct this issue.

I have been working with Dell's Gold support for a few weeks and have not been able to find any problem with the hardware. I'm almost wondering if there is a design problem; perhaps related to having such a large RAID 5 array.

sphbecker · Answer

Perfmon shows the system as virtually idle expect for the Avg. Disk Que Length goes through the roof (often up to 60). It takes a very long time for users to open files; the system performs slowly locally and running a backup takes days.

I have already been through all the common troubleshooting steps with Dell's gold support. I was hoping someone would see an issue with my configuration. Like "Oh, R2 doesn't work correctly with that array controller" or "that server has an issue with arrays larger than 1TB."

OptikConnex · Answer

Since all hardware seems well and since you seem to have your systems pretty beefed up I would look at the RAID 5 issue first. Before I say that, you say "performance issues", can you describe this better? Does it take forever for a user to open the file off the network?, or Are the servers peaking out in memory or processor usage? (user perfmon) etc...

Let me know and I can better give an opinion.

OptikConnex · Answer

The disk queue being so high leads me to believe it IS a hard drive/RAID issue. The drives cannot keep up fast enough with reads and writes. We had the same problem with an HP ProLiant server (our database sever) had plenty of processor and memory power but the disk queue was through the roof. We ended up going with a RAMSAN for our solution, so now all read/writes are done on the RAMSAN (which is basically a server full of memory which writes data to the hard drives when it has time, it also has it's own built in battery backup so if a power down it will write the data to disk before going down.) That is the only solution I see for you at this point. YES, you could try switching to a RAID 0/1 or RAID10 to see if you gain performance improvements. Is it by chance network traffic interfering as well?

sphbecker · Answer

Our traffic should not but putting that kind of a load on these servers (at least I don't see why it would).  Users immodestly started complaining when we 'upgraded' from a PE2500 to these PE2800 servers.  And as I said, my laptop's internal hard drive can out-perform the these disk arrays even in isolated tests.

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PE 2800 Performance Problems

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