I have size of 2.

We know about this risk and we accept it, but we still don't know why performance so so bad.

Cheers,

Rafał Wądołowski

On 04.01.2018 16:51, c...@elchaka.de wrote:
I assume you have size of 3 then divide your expected 400 with 3 and you are not far Away from what you get...

In Addition you should Never use Consumer grade ssds for ceph as they will be reach the DWPD very soon...

Am 4. Januar 2018 09:54:55 MEZ schrieb "Rafał Wądołowski" <rwadolow...@cloudferro.com>:

    Hi folks,

    I am currently benchmarking my cluster for an performance issue and I
    have no idea, what is going on. I am using these devices in qemu.

    Ceph version 12.2.2

    Infrastructure:

    3 x Ceph-mon

    11 x Ceph-osd

    Ceph-osd has 22x1TB Samsung SSD 850 EVO 1TB

    96GB RAM

    2x E5-2650 v4

    4x10G Network (2 seperate bounds for cluster and public) with MTU 9000


    I had tested it with rados bench:

    # rados bench -p rbdbench 30 write -t 1

    Total time run:         30.055677
    Total writes made:      1199
    Write size:             4194304
    Object size:            4194304
    Bandwidth (MB/sec):     159.571
    Stddev Bandwidth:       6.83601
    Max bandwidth (MB/sec): 168
    Min bandwidth (MB/sec): 140
    Average IOPS:           39
    Stddev IOPS:            1
    Max IOPS:               42
    Min IOPS:               35
    Average Latency(s):     0.0250656
    Stddev Latency(s):      0.00321545
    Max latency(s):         0.0471699
    Min latency(s):         0.0206325

    # ceph tell osd.0 bench
    {
          "bytes_written": 1073741824,
          "blocksize": 4194304,
          "bytes_per_sec": 414199397
    }

    Testing osd directly

    # dd if=/dev/zero of=/dev/sdc bs=4M oflag=direct count=100
    100+0 records in
    100+0 records out
    419430400 bytes (419 MB, 400 MiB) copied, 1.0066 s, 417 MB/s

    When I do dd inside vm (bs=4M wih direct), I have result like in rados
    bench.

    I think that the speed should be arround ~400MB/s.

    Is there any new parameters for rbd in luminous? Maybe I forgot about
    some performance tricks? If more information needed feel free to ask.



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