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#1: md: raid5 vs raid10 (f2,n2,o2) benchmarks [w/10 raptors]

Posted on 2008-03-29 19:20:03 by Justin Piszcz

There has been a lot of discussion on the mailing list regarding the
various raid10 replicas so I benchmarked them compared to RAID 5 all with
no optimizations and then re-ran the tests with optimizations, RAID 5
still generally turns out the best speed for sequential writes but
raid10_f2 seems to overtake raid5 for reads.

All tests used the XFS filesystem.

For the results that show 0 this is when bonnie++ reports '+++' for the result
which means it went too fast and needed to capture more data to give an
accurate number; however, I was only interested in the sequential read and
write speeds. All tests are with default mkfs.xfs options, where I used
optimizations for the filesystem, these are only mount option parameters
as follows: noatime,nodiratime,logbufs=8,logbsize=262144. I have done a lot
of testing in the past with mkfs.xfs and its default parameters optimize
to a physical HDD or mdraid so there is little point/gain to try to optimize
it any further.


I have gone back to my RAID 5 optimized configuration, I am done testing
for now :)

1. Test RAID 10 with no optimizations to the disks or filesystems.
a. mdadm --create /dev/md3 --assume-clean --chunk=256 --level=raid10 --raid-devices=10 --spare-devices=0 --layout=f2 /dev/sd[c-l]1
b. mdadm --create /dev/md3 --assume-clean --chunk=256 --level=raid10 --raid-devices=10 --spare-devices=0 --layout=n2 /dev/sd[c-l]1
c. mdadm --create /dev/md3 --assume-clean --chunk=256 --level=raid10 --raid-devices=10 --spare-devices=0 --layout=o2 /dev/sd[c-l]1
2. Test RAID 5 with no optimizations as well using the default layout.
a. mdadm --create /dev/md3 --assume-clean --chunk=256 --level=raid5 --raid-devices=10 --spare-devices=0 /dev/sd[c-l]1
3. Test RAID 5 with optimizations.
a. mdadm --create /dev/md3 --assume-clean --chunk=1024 --level=raid5 --raid-devices=10 --spare-devices=0 /dev/sd[c-l]1

2. Format and set permissions and run benchmarks.
a. mkfs.xfs -f /dev/md3; mount /dev/md3 /r1; mkdir /r1/x
chown -R jpiszcz:users /r1

3. Run the following bonnie++ benchmark 3 times and take the average.
a. /usr/bin/time /usr/sbin/bonnie++ -d /x/test -s 16384 -m p34 -n 16:100000:16:64
b. A script will be responsible for running it 3 times and the total time
of all runs will also be taken.

a. Total time for f2: 34:35.75elapsed 69%CPU
b. bonnie++ csv line below:
p34_f2,16G,79314.7,99,261108,43,110668,14,82252,99,529999,38 .6667,866.333,1,16:100000:16/64,5910.67,43.3333,0,0,10761,48 .3333,6586,47.6667,0,0,9575.33,50

c. Total time for n2: 36:39.66elapsed 67%CPU
d. bonnie++ csv line below:
p34_n2,16G,76630.3,99,290732,48.3333,118666,16,80120.3,99,21 6790,16,915.433,1,16:100000:16/64,3973.33,29.6667,9661,20,19 641.3,87.6667,5568,40.6667,0,0,10982.3,57.3333

e. Total time for o2: 35:51.84elapsed 67%CPU
f. bonnie++ csv line below:
p34_o2,16G,79096.3,99,288396,47,130531,17,80963.3,99,205556, 14,867.267,1,16:100000:16/64,5490,40.3333,0,0,9218,41.6667,7 504,54.6667,0,0,9896,52

g. Total time for raid5 (256 KiB chunk): 45:44.73elapsed 54%CPU
h. bonnie++ csv line below:
p34_r5d,16G,76698,99,156443,25.6667,83565.7,14.3333,80975.3, 98.3333,318142,22.3333,691.067,1,16:100000:16/64,864,7.33333 ,6716.33,17,542,3.33333,868.333,7.33333,6642,18,491,3.33333

a. Total time for f2 (block+fs optimizations): 33:33.13elapsed 72%CPU
b. bonnie++ csv line below:
p34o_f2,16G,79408.7,99,271643,45,133114,17.3333,80911.3,99,4 36018,31.3333,887.233,1,16:100000:16/64,5649,41.6667,0,0,179 81.7,78.3333,4830,36.3333,0,0,17068.7,95

c. Total time for n2 (block+fs optimizations): 33:45.89elapsed 72%CPU
d. bonnie++ csv line below:
p34o_n2,16G,79750,99,272355,45,148752,20,81030.3,99,288662,2 1,926.733,1,16:100000:16/64,6797.67,50.3333,10022.3,23,12250 ,56.3333,5875,43.3333,0,0,18063.3,97.3333

e. Total time for o2 (block+fs optimizations): 34:54.18elapsed 69%CPU
f. bonnie++ csv line below:
p34o_o2,16G,79807,99,266949,44,147301,19.3333,80913.3,98.666 7,216350,15,853.3,1,16:100000:16/64,6397.33,47.6667,0,0,1913 0,84.3333,5833.67,43.3333,0,0,13921.7,75.3333

i. Total time for raid5 (1024 KiB chunk)(block+fs optimizations)
32:02.28elapsed 79%CPU
j. bonnie++ csv line below:
p34o_r5d,16G,75961,99,389603,84.6667,185017,31.3333,81636.7, 99,496843,36,659.467,1,16:100000:16/64,2836,24,10498,29,2842 .67,18,4686.33,50.6667,13650.3,46.6667,2419.67,19

1. Problem found with mkfs.xfs using such a large stripe size with RAID10:
# mkfs.xfs /dev/md3 -f
log stripe unit (1048576 bytes) is too large (maximum is 256KiB)
log stripe unit adjusted to 32KiB
2. I will use 256 KiB for all RAID 10 testing.
and the non-optimized RAID 5 test.

Other misc info for RAID 10:
p34:~# mkfs.xfs /dev/md3 -f
meta-data=/dev/md3 isize=256 agcount=32, agsize=5723456 blks
= sectsz=512 attr=2
data = bsize=4096 blocks=183150592, imaxpct=25
= sunit=64 swidth=640 blks
naming =version 2 bsize=4096
log =internal log bsize=4096 blocks=32768, version=2
= sectsz=512 sunit=64 blks, lazy-count=0
realtime =none extsz=2621440 blocks=0, rtextents=0

p34:~# mount /dev/md3 /r1

p34:~# df -h
/dev/md3 699G 5.1M 699G 1% /r1

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