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

[Justin Piszcz]

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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