|
Hi, all
I have yet to find a good solution, and some one have any
suggestions.
I think this is a big problem when you use cache
tier.
2015-08-03
liukai
发件人：Kenneth Waegeman
<kenneth.waegeman@xxxxxxxx>
发送时间：2015-07-30 17:31
主题：Re: [ceph-users] A cache tier
issue with rate only at 20MB/s when data move from cold pool to hot
pool
收件人："liukai"<liukai@xxxxxxxxxxxxx>,"ceph-users"<ceph-users@xxxxxxxx>
抄送：
On 06/16/2015 01:17 PM, Kenneth Waegeman wrote:
> Hi!
>
> We also see this at our site: When we cat a large file from cephfs to
> /dev/null, we get about 10MB/s data transfer. I also do not see a
> system resource bottleneck.
> Our cluster consists of 14 servers with each 16 disks, together forming
> a EC coded pool. We also have 2SSDs per server for the cache. Running
> 0.94.1
Hi,
Does someone has an idea about this? Is there some debugging or testing
we can do to find the problem here?
Thank you!
Kenneth
>
> So we are having the same question.
>
> Our cache pool is in writeback mode, can it help to set it in readonly
> for this?
>
> Kenneth
>
> On 06/16/2015 12:58 PM, liukai wrote:
>> Hi all，
>> A cache tier, 2 hot node with 8 ssd osd, and 2 cold node with 24 sata
>> osd.
>>
>> The public network rate is 10000Mb/s and cluster network rate is
>> 1000Mb/s.
>>
>> Using fuse-client to access the files.
>> The issue is:
>>
>> When the files are in hot pool, the copy rate is very fash.
>>
>> But when the files are only in cold pool, the rate only reach 20MB/s.
>>
>> I known that when files are not in the hot pool, the files should
>> been copy from cold pool to hot pool first, and then from hot pool to
>> client.
>>
>> But the cpu, ram and network seems not the bottleneck. and will be
>> the cause of system design?
>>
>> Are there some params to adjust to improve the rate from cold pool to
>> hot pool?
>>
>> Thanks
>> 2015-06-16
>> ------------------------------------------------------------------------
>> liukai
>>
>>
>> _______________________________________________
>> ceph-users mailing list
>> ceph-users@xxxxxxxxxxxxxx
>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>
> _______________________________________________
> ceph-users mailing list
> ceph-users@xxxxxxxxxxxxxx
> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com |
_______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
