You haven’t stated what size replication you are running. Keep in mind that with a replication factor of 3, you will be writing 6x the amount of data down to disks than what the benchmark says (3x replication x2 for data+journal write).
You might actually be near the hardware maximums. What does iostat looks like whilst you are running rados bench, are the disks getting maxed out?
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Marek Dohojda
Sent: 24 November 2015 16:27
To: Alan Johnson <alanj@xxxxxxxxxxxxxx>
7 total servers, 20 GIG pipe between servers, both reads and writes. The network itself has plenty of pipe left, it is averaging 40Mbits/s
Rados Bench SAS 30 writes
Total time run: 30.591927
Total writes made: 386
Write size: 4194304
Bandwidth (MB/sec): 50.471
Stddev Bandwidth: 48.1052
Max bandwidth (MB/sec): 160
Min bandwidth (MB/sec): 0
Average Latency: 1.25908
Stddev Latency: 2.62018
Max latency: 21.2809
Min latency: 0.029227
Rados Bench SSD writes
Total time run: 20.425192
Total writes made: 1405
Write size: 4194304
Bandwidth (MB/sec): 275.150
Stddev Bandwidth: 122.565
Max bandwidth (MB/sec): 576
Min bandwidth (MB/sec): 0
Average Latency: 0.231803
Stddev Latency: 0.190978
Max latency: 0.981022
Min latency: 0.0265421
As you can see SSD is better but not as much as I would expect SSD to be.
On Tue, Nov 24, 2015 at 9:10 AM, Alan Johnson <alanj@xxxxxxxxxxxxxx> wrote:
Hard to know without more config details such as no of servers, network – GigE or !0 GigE, also not sure how you are measuring, (reads or writes) you could try RADOS bench as a baseline, I would expect more performance with 7 X 10K spinners journaled to SSDs. The fact that SSDs did not perform much better may mean to a bottleneck elsewhere – network perhaps?
From: Marek Dohojda [mailto:mdohojda@xxxxxxxxxxxxxxxxxxx]
Sent: Tuesday, November 24, 2015 10:37 AM
To: Alan Johnson
Cc: Haomai Wang; ceph-users@xxxxxxxxxxxxxx
Subject: Re: Performance question
Yeah they are, that is one thing I was planning on changing, What I am really interested at the moment, is vague expected performance. I mean is 100MB around normal, very low, or "could be better"?
On Tue, Nov 24, 2015 at 8:02 AM, Alan Johnson <alanj@xxxxxxxxxxxxxx> wrote:
Are the journals on the same device – it might be better to use the SSDs for journaling since you are not getting better performance with SSDs?
From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of Marek Dohojda
Sent: Monday, November 23, 2015 10:24 PM
To: Haomai Wang
Cc: ceph-users@xxxxxxxxxxxxxx
Subject: Re: Performance question
Sorry I should have specified SAS is the 100 MB :) , but to be honest SSD isn't much faster.
On Mon, Nov 23, 2015 at 7:38 PM, Haomai Wang <haomaiwang@xxxxxxxxx> wrote:
On Tue, Nov 24, 2015 at 10:35 AM, Marek Dohojda
<mdohojda@xxxxxxxxxxxxxxxxxxx> wrote:
> No SSD and SAS are in two separate pools.
>
> On Mon, Nov 23, 2015 at 7:30 PM, Haomai Wang <haomaiwang@xxxxxxxxx> wrote:
>>
>> On Tue, Nov 24, 2015 at 10:23 AM, Marek Dohojda
>> <mdohojda@xxxxxxxxxxxxxxxxxxx> wrote:
>> > I have a Hammer Ceph cluster on 7 nodes with total 14 OSDs. 7 of which
>> > are
>> > SSD and 7 of which are SAS 10K drives. I get typically about 100MB IO
>> > rates
>> > on this cluster.
So which pool you get with 100 MB?>> > http://xo4t.mj.am/link/xo4t/rsxjit1/1/NlEqhua2rOHxmXdiOCL_wA/aHR0cDovL2xpc3RzLmNlcGguY29tL2xpc3RpbmZvLmNnaS9jZXBoLXVzZXJzLWNlcGguY29t
>>
>> You mixed up sas and ssd in one pool?
>>
>> >
>> > I have a simple question. Is 100MB within my configuration what I
>> > should
>> > expect, or should it be higher? I am not sure if I should be looking for
>> > issues, or just accept what I have.
>> >
>> > _______________________________________________
>> > ceph-users mailing list
>> > ceph-users@xxxxxxxxxxxxxx
>> >
>>
>>
>>
>> --
>> Best Regards,
>>
>> Wheat
>
>--
Best Regards,
Wheat
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