Hi Lin,
Yes it will read from the primary osd, but for the reasons stated this
should not impact performance.
Maged
On 2018-01-26 19:52, shadow_lin wrote:
> Hi Maged,
> I just want to make sure if I understand how ceph client read from cluster.So
> with current version of ceph(12.2.2) the client only read from the primary
> osd(one copy),is that true?
>
> 2018-01-27
> -------------------------
>
> lin.yunfan
> -------------------------
>
> 发件人：Maged Mokhtar <mmokh...@petasan.org>
> 发送时间：2018-01-26 20:27
> 主题：Re: [ceph-users] How ceph client read data from ceph cluster
> 收件人："shadow_lin"<shadow_...@163.com>
> 抄送："ceph-users"<ceph-users@lists.ceph.com>
>
> On 2018-01-26 09:09, shadow_lin wrote:
> Hi List,
> I read a old article about how ceph client read from ceph cluster.It said the
> client only read from the primary osd. Since ceph cluster in replicate mode
> have serveral copys of data only read from one copy seems waste the
> performance of concurrent read from all the copys.
> But that artcile is rather old so maybe ceph has imporved to read from all
> the copys? But I haven't find any info about that.
> Any info about that would be appreciated.
> Thanks
>
> 2018-01-26
> -------------------------
> shadow_lin
> _______________________________________________
> ceph-users mailing list
> ceph-users@lists.ceph.com
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>
> Hi
>
> The majority of cases you will have more concurrent io requests than disks,
> so the load will already be distributed evenly. If this is not the case and
> you have a large cluster with fewer clients, you may consider using
> object/rbd striping so each io will be divided into different osd requests.
>
> Maged
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