thanks. now i use fio to test random write performance
why the random write performance is so low, 6X SSD , 4k IOPS write random only 55097? when I use FIO,the single SSD random 4k write reach to 3.5W.
root@host0:/# fio -filename=/dev/md0 -iodepth=16 -thread -rw=randwrite -ioengine=libaio -bs=4k -size=30G -numjobs=10 -runtime=1000 -group_reporting -name=mytest
mytest: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=16
...
mytest: (g=0): rw=randwrite, bs=4K-4K/4K-4K, ioengine=libaio, iodepth=16
fio 1.59
Starting 10 threadsJobs: 1 (f=1): [____w_____] [68.3% done] [0K/0K /s] [0 /0 iops] [eta 07m:53s] s]
mytest: (groupid=0, jobs=10): err= 0: pid=6099
write: io=215230MB, bw=220392KB/s, iops=55097 , runt=1000019msec
slat (usec): min=1 , max=337733 , avg=176.46, stdev=2623.23
clat (usec): min=4 , max=540048 , avg=2667.83, stdev=10078.16
lat (usec): min=40 , max=576049 , avg=2844.42, stdev=10399.30
bw (KB/s) : min= 0, max=1100192, per=10.22%, avg=22514.48, stdev=17262.85
cpu : usr=6.70%, sys=16.48%, ctx=11656865, majf=46, minf=1626216
IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=100.0%, 32=0.0%, >=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.1%, 32=0.0%, 64=0.0%, >=64=0.0%
issued r/w/d: total=0/55098999/0, short=0/0/0
lat (usec): 10=0.01%, 50=41.01%, 100=50.01%, 250=1.23%, 500=0.42%
lat (usec): 750=0.02%, 1000=0.01%
lat (msec): 2=0.01%, 4=0.01%, 10=0.05%, 20=0.16%, 50=6.58%
lat (msec): 100=0.44%, 250=0.05%, 500=0.01%, 750=0.01%
Run status group 0 (all jobs):
WRITE: io=215230MB, aggrb=220391KB/s, minb=225681KB/s, maxb=225681KB/s, mint=1000019msec, maxt=1000019msec
Disk stats (read/write):
md0: ios=167/49755890, merge=0/0, ticks=0/0, in_queue=0, util=0.00%, aggrios=12530125/13199536, aggrmerge=1151802/1283069, aggrticks=14762174/11503916, aggrin_queue=26230996, aggrutil=95.56%
sdh: ios=12519812/13192529, merge=1157990/1291154, ticks=11854444/8141456, in_queue=19960416, util=90.19%
sdi: ios=12524619/13201735, merge=1158477/1280984, ticks=12161064/8308572, in_queue=20436280, util=90.56%
sdj: ios=12526628/13210796, merge=1155512/1274875, ticks=12074040/8250524, in_queue=20289960, util=90.63%
sdk: ios=12534367/13213646, merge=1148527/1268088, ticks=12372792/8455368, in_queue=20791752, util=90.81%
sdl: ios=12534777/13205894, merge=1147263/1275381, ticks=12632824/8728444, in_queue=21325724, util=90.86%
sdm: ios=12540551/13172620, merge=1143048/1307937, ticks=27477880/27139136, in_queue=54581844, util=95.56%
------------------------------------------------------------------
发件人：Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx>
发送时间：2013年11月29日(星期五) 10:38
收件人：lilofile <lilofile@xxxxxxxxxx>; Linux RAID <linux-raid@xxxxxxxxxxxxxxx>
主 题：Re: 答复：答复：md raid5 performace 6x SSD RAID5
On 11/28/2013 4:02 AM, lilofile wrote:
> thank you for your advise. now I have test multi-thread patch, the single raid5 performance improve 30%.
>
> but I have another problem,when write on single raid,write performance is approx 1.1GB/s
...
> [1]- Done dd if=/dev/zero of=/dev/md126 count=100000 bs=1M
> [2]+ Done dd if=/dev/zero of=/dev/md127 count=100000 bs=1M
No. This is not a parallel IO test.
...
> To address #3 use FIO or a similar testing tool that can issue IOs in
> parallel. With SSD based storage you will never reach maximum
> throughput with a serial data stream.
This is a parallel IO test, one command line:
~# fio --directory=/dev/md126 --zero_buffers --numjobs=16
--group_reporting --blocksize=64k --ioengine=libaio --iodepth=16
--direct=1 --size=64g --name=read --rw=read --stonewall --name=write
--rw=write --stonewall
Normally this targets a filesystem, not a raw block device. This
command line should work for a raw md device.
--
Stan
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