On Thu, 29 May 2008, Holger Kiehl wrote:
On Wed, 28 May 2008, 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
Why is the Sequential Output (Block) for raid6 165719 and for raid5 only
86797? I would have thought that raid6 was always a bit slower in writting
due to having to write double amount of parity data.
Holger
RAID5 (2nd test of 3 averaged runs) & Single disk added:
http://home.comcast.net/~jpiszcz/raid/20080528/raid-levels.html
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