Raid 5 Performance - Perc 5/i

E

EvilAlchemist

2[H]4U
Joined
Jan 11, 2008
Messages
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I wanted to make sure my Raid 5 Setup is running at the level it should.

This is my First Raid setup, so I have no real #'s to go on.

E6420 @ 2.13 Ghz
Abit IP35-Pro Motherboard
4GB DDR2 800Mhz
Dell Perc 5/i with 512 MB RAM
6 x WD 6400AAKS
Stripe Size: 64K


Do These Number Look Correct for this Card & Raid Type?

64K Block Size Test
64Kread.png


512K Block Size Test
512KRead.png


1MB Block Size Test
1MBRead.png


8MB Block Size Test
8MBRead.png


 
I am going to assume that those numbers look about right since only one person has said anything.
 
Evil, I'd say it pretty well passes the sniff test.

A quick bit of fuzzy math... 6 total disks in the RAID5, with 5 of those contributing to the sustained read speed (1 out for parity)... each with about a 90MBps sustained rate ~= 450MBps estimated sustained average read.

I was a bit surprised by how low the sustained read was on 64k blocks, but it popped up to where we'd expect it more on the larger block sizes. Dependent upon your usage (average file size), you may not want to go with the big 8MB block size, even though it gives the highest sequential perf... just because it'll be inefficient for small files. If you're using large files (> 5x8MB... i.e. >40MB) then 8MB blocks are dandy because you're not losing space to partially unused blocks.

-cheers and good luck-

EDIT: if you need a quick boost to that performance, just shove a few tamales into that Perc and it oughta give you a bit extra :cool:
 
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