On Sat, Jun 7, 2008 at 7:22 AM, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote: > First, the original benchmarks with 6-SATA drives with fixed formatting, > using > right justification and the same decimal point precision throughout: > http://home.comcast.net/~jpiszcz/20080607/raid-benchmarks-decimal-fix-and-right-justified/disks.html > > Now for for veliciraptors! Ever wonder what kind of speed is possible with > 3 disk, 4,5,6,7,8,9,10-disk RAID5s? I ran a loop to find out, each run is > executed three times and the average is taken of all three runs per each > RAID5 disk set. > > In short? The 965 no longer does justice with faster drives, a new chipset > and motherboard are needed. After reading or writing to 4-5 veliciraptors > it saturates the bus/965 chipset. > > Here is a picture of the 12 veliciraptors I tested with: > http://home.comcast.net/~jpiszcz/20080607/raid5-benchmarks-3to10-veliciraptors/raptors.jpg > > Here are the bonnie++ results: > http://home.comcast.net/~jpiszcz/20080607/raid5-benchmarks-3to10-veliciraptors/veliciraptor-raid.html > > For those who want the results in text: > http://home.comcast.net/~jpiszcz/20080607/raid5-benchmarks-3to10-veliciraptors/veliciraptor-raid.txt > > System used, same/similar as before: > Motherboard: Intel DG965WH > Memory: 8GiB > Kernel: 2.6.25.4 > Distribution: Debian Testing x86_64 > Filesystem: XFS with default mkfs.xfs parameters [auto-optimized for SW > RAID] > Mount options: defaults,noatime,nodiratime,logbufs=8,logbsize=262144 0 1 > Chunk size: 1024KiB > RAID5 Layout: Default (left-symmetric) > Mdadm Superblock used: 0.90 > > Optimizations used (last one is for the CFQ scheduler), it improves > performance by a modest 5-10MiB/s: > http://home.comcast.net/~jpiszcz/raid/20080601/raid5.html > > # Tell user what's going on. > echo "Optimizing RAID Arrays..." > > # Define DISKS. > cd /sys/block > DISKS=$(/bin/ls -1d sd[a-z]) > > # Set read-ahead. > # > That's actually 65k x 512byte blocks so 32MiB > echo "Setting read-ahead to 32 MiB for /dev/md3" > blockdev --setra 65536 /dev/md3 > > # Set stripe-cache_size for RAID5. > echo "Setting stripe_cache_size to 16 MiB for /dev/md3" Sorry to sound like a broken record, 16MiB is not correct. size=$((num_disks * 4 * 16384 / 1024)) echo "Setting stripe_cache_size to $size MiB for /dev/md3" ...and commit 8b3e6cdc should improve the performance / stripe_cache_size ratio. > 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 > > # Fix slice_idle. > # See http://www.nextre.it/oracledocs/ioscheduler_03.html > echo "Fixing slice_idle to 0..." > for i in $DISKS > do > echo "Changing slice_idle to 0 on $i" > echo 0 > /sys/block/"$i"/queue/iosched/slice_idle > done > Thanks for putting this data together. Regards, Dan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
