Re: Raid6 write performance

["Keld Jørn Simonsen" <keld@dkuug.dk>]

On Mon, Jan 19, 2009 at 03:10:01AM -0500, thomas62186218@aol.com wrote:
> 
> I tested RAID 5 and RAID 6 with 12 x 15K SAS drives on Ubuntu 8.04 
> 64-bit and found their performance to be about the same. I used 256 K 
> chunk size, v1.0 superblocks, stripecachesize of 16384, and readahead 
> of 65536.
> 
> RAID 5 reads: 774 MB/sec
> RAID 5 writes: 585 MB/sec
> 
> RAID 6 reads: 742 MB/sec
> RAID 6 writes: 559 MB/sec
> 
> My CPU utilization remains under 10% though during writes, and I'm 
> wondering what can be done to get write performance closer to read 
> performance. I have dual quad-core CPUs so there's plenty of CPU to go 
> around. Any ideas on that front?

Seems like it is the same equipment that you also did the raid10,f2
tests for. I think it would be interesting to have a consolidated list
of performance comparisons, when you have completed your tweakings.
Is that part of your plan?

best regards
keld