Hello Huan,
If you look at Sebestien blog (
https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/)
at comment section. You can see that Samsung SSD behaves very and very
poorly on tests:
Samsung SSD 850 PRO 256GB
409600000 bytes (410 MB) copied, 274.162 s, 1.5 MB/s
INTEL 535 SSDSC2BW240H6 240GB
409600000 bytes (410 MB) copied, 1022.64 s, 401 kB/s
If you have similar disks, you should not use it in Ceph.
On Fri, Feb 12, 2016 at 10:14 AM, Huan Zhang <huan.zhang...@gmail.com>
wrote:
> Thanks for reply!
> not very good, but seems acceptable, how do you think the possible
> reasons? osd erf counters helpful for this?
>
>
> sudo fio --filename=/dev/sda2 --direct=1 --sync=1 --rw=write --bs=4k
> --numjobs=1 --iodepth=1 --runtime=60 --time_based --group_reporting
> --name=journal-test
>
> journal-test: (g=0): rw=write, bs=4K-4K/4K-4K/4K-4K, ioengine=sync,
> iodepth=1
>
> fio-2.1.11
>
> Starting 1 process
>
> Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/49928KB/0KB /s] [0/12.5K/0 iops]
> [eta 00m:00s]
>
> journal-test: (groupid=0, jobs=1): err= 0: pid=247168: Fri Feb 12 16:08:12
> 2016
>
> write: io=2944.1MB, bw=50259KB/s, iops=12564, runt= 60001msec
>
> clat (usec): min=43, max=1503, avg=77.47, stdev=17.37
>
> lat (usec): min=43, max=1503, avg=77.75, stdev=17.42
>
> clat percentiles (usec):
>
> | 1.00th=[ 47], 5.00th=[ 50], 10.00th=[ 54], 20.00th=[ 63],
>
> | 30.00th=[ 67], 40.00th=[ 73], 50.00th=[ 76], 60.00th=[ 79],
>
> | 70.00th=[ 86], 80.00th=[ 91], 90.00th=[ 100], 95.00th=[ 105],
>
> | 99.00th=[ 122], 99.50th=[ 129], 99.90th=[ 147], 99.95th=[ 155],
>
> | 99.99th=[ 167]
>
> bw (KB /s): min=44200, max=57680, per=100.00%, avg=50274.42,
> stdev=2662.04
>
> lat (usec) : 50=4.64%, 100=84.85%, 250=10.51%, 500=0.01%, 750=0.01%
>
> lat (msec) : 2=0.01%
>
> cpu : usr=6.34%, sys=32.72%, ctx=1507971, majf=0, minf=98
>
> IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 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=0.0%, 32=0.0%, 64=0.0%,
> >=64=0.0%
>
> issued : total=r=0/w=753897/d=0, short=r=0/w=0/d=0
>
> latency : target=0, window=0, percentile=100.00%, depth=1
>
>
> Run status group 0 (all jobs):
>
> WRITE: io=2944.1MB, aggrb=50258KB/s, minb=50258KB/s, maxb=50258KB/s,
> mint=60001msec, maxt=60001msec
>
>
> Disk stats (read/write):
>
> sda: ios=0/1506216, merge=0/0, ticks=0/39449, in_queue=39025, util=65.04%
>
>
> 2016-02-12 15:41 GMT+08:00 Huan Zhang <huan.zhang...@gmail.com>:
>
>> Hi,
>>
>> ceph VERY SLOW with 24 osd(SAMSUNG ssd).
>> fio /dev/rbd0 iodepth=1 direct=1 IOPS only ~200
>> fio /dev/rbd0 iodepth=32 direct=1 IOPS only ~3000
>>
>> But test single ssd deive with fio:
>> fio iodepth=1 direct=1 IOPS ~15000
>> fio iodepth=32 direct=1 IOPS ~30000
>>
>> Why ceph SO SLOW? Could you give me some help?
>> Appreciated!
>>
>>
>> My Enviroment:
>> [root@szcrh-controller ~]# ceph -s
>> cluster eb26a8b9-e937-4e56-a273-7166ffaa832e
>> health HEALTH_WARN
>> 1 mons down, quorum 0,1,2,3,4 ceph01,ceph02,ceph03,ceph04,
>> ceph05
>> monmap e1: 6 mons at {ceph01=
>>
>> 10.10.204.144:6789/0,ceph02=10.10.204.145:6789/0,ceph03=10.10.204.146:6789/0,ceph04=10.10.204.147:6789/0,ceph05=10.10.204.148:6789/0,ceph06=0.0.0.0:0/5
>> }
>> election epoch 6, quorum 0,1,2,3,4
>> ceph01,ceph02,ceph03,ceph04,ceph05
>> osdmap e114: 24 osds: 24 up, 24 in
>> flags sortbitwise
>> pgmap v2213: 1864 pgs, 3 pools, 49181 MB data, 4485 objects
>> 144 GB used, 42638 GB / 42782 GB avail
>> 1864 active+clean
>>
>> [root@ceph03 ~]# lsscsi
>> [0:0:6:0] disk ATA SAMSUNG MZ7KM1T9 003Q /dev/sda
>> [0:0:7:0] disk ATA SAMSUNG MZ7KM1T9 003Q /dev/sdb
>> [0:0:8:0] disk ATA SAMSUNG MZ7KM1T9 003Q /dev/sdc
>> [0:0:9:0] disk ATA SAMSUNG MZ7KM1T9 003Q /dev/sdd
>>
>
>
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