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
That's actually 65k x 512byte blocks so 32MiB
# 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.
Results are meaningless without a crucial detail - what was the chunk size
used during array creation time? Otherwise interesting test :)
Cheers
Peter
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