Very slow disk performance on Dell PowerEdge 2950 w/ PERC 6/i running RAID 10

Posted by vocoder on Server Fault See other posts from Server Fault or by vocoder
Published on 2012-03-30T20:07:37Z Indexed on 2012/11/29 11:09 UTC
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linux

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ubuntu

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dell

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perc

I recently set up a server running Ubuntu 10.04 LTS on a Dell PowerEdge 2950 server - it has 6 500 gb 7200RPM SATA drives setup in a RAID 10 config.

I am seeing extremely poor disk performance - the RAID array reports all disks are normal and using MegaCLI, it looks like the BBU is fine.

hdparm -tT /dev/sda reports:

Timing cached reads: 90 MB in 2.05 seconds = 43.96 MB/sec
Timing buffered disk reads: 24 MB in 3.11 seconds = 7.72 MB/sec

So as you can see, it takes forever to something as simple as an apt-get upgrade and even logging into the server.

How do I go about troubleshooting what is causing this? I upgraded the firmware on the PERC 6i RAID controller to the latest, but didn't see any improvements.

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