Re: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++)

[Keld Jørn Simonsen]

I added this in the wiki performance section.
I think it would have been informative if also a test with one drive in
a non-raid setup was described.

Are there any particular findings you want to highlight?

Is there some way to estimate random read and writes from this test?

Are the XFS file systems completely new when running the tests?

Best regards
keld

On Wed, May 28, 2008 at 04:53:47AM -0400, Justin Piszcz wrote:
> Hardware:
> 
> 1. Utilized (6) 400 gigabyte sata hard drives.
> 2. Everything is on PCI-e (965 chipset & a 2port sata card)
> 
> Used the following 'optimizations' for all tests.
> 
> # Set read-ahead.
> echo "Setting read-ahead to 64 MiB for /dev/md3"
> blockdev --setra 65536 /dev/md3
> 
> # Set stripe-cache_size for RAID5.
> echo "Setting stripe_cache_size to 16 MiB for /dev/md3"
> echo 16384 > /sys/block/md3/md/stripe_cache_size
> 
> # Disable NCQ on all disks.
> echo "Disabling NCQ on all disks..."
> for i in $DISKS
> do
>   echo "Disabling NCQ on $i"
>   echo 1 > /sys/block/"$i"/device/queue_depth
> done
> 
> Software:
> 
> Kernel: 2.6.23.1 x86_64
> Filesystem: XFS
> Mount options: defaults,noatime
> 
> Results:
> 
> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.html
> http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.txt
> 
> Note: 'deg' means degraded and the number after is the number of disks 
> failed, I did not test degraded raid10 because there are many ways you can 
> degrade a raid10; however, the 3 types of raid10 were benchmarked 
> f2,n2,o2.
> 
> Each test was run 3 times and averaged--FYI.
> 
> Justin.
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