Messages in this thread | | | Date | Thu, 29 May 2008 13:02:40 -0400 (EDT) | From | Justin Piszcz <> | Subject | Re: Performance Characteristics of All Linux RAIDs (mdadm/bonnie++) |
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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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