Hello,
thanks for you answer the question.
But when there are less than 50 thousand objects, and latency is very big . I
see the write ops for the bucket index object.， from
"journaled_completion_queue" to "op_commit" cost 3.6 seconds，this mean that
from “writing journal finish” to "op_commit" cost 3.6 seconds。
so I can't understand this and what happened?
thanks
baijia...@126.com
发件人： Guang Yang
发送时间： 2014-06-30 14:57
收件人： baijiaruo
抄送： ceph-users
主题： Re: [ceph-users] Ask a performance question for the RGW
Hello,
There is a known limitation of bucket scalability, and there is a blueprint
tracking it -
https://wiki.ceph.com/Planning/Blueprints/Submissions/rgw%3A_bucket_index_scalability.
At time being, I would recommend to do sharding at application level (create
multiple buckets) to workaround this limitation.
Thanks,
Guang
On Jun 30, 2014, at 2:54 PM, baijia...@126.com wrote:
>
> hello, everyone!
>
> when I user rest bench test RGW performance and the cmd is:
> ./rest-bench --access-key=ak --secret=sk --bucket=bucket_name --seconds=600
> -t 200 -b 524288 -no-cleanup write
>
> test result:
> Total time run: 362.962324 T
> otal writes made: 48189
> Write size: 524288
> Bandwidth (MB/sec): 66.383
> Stddev Bandwidth: 40.7776
> Max bandwidth (MB/sec): 173
> Min bandwidth (MB/sec): 0
> Average Latency: 1.50435
> Stddev Latency: 0.910731
> Max latency: 9.12276
> Min latency: 0.19867
>
> my environment is 4 host and 40 disk（osd）。 but test result is very bad，
> average latency is 1.5 seconds 。and I find write obj metadate is very
> slowly。because it puts so many object to one bucket， we know writing object
> metadate can call method “bucket_prepare_op”,and test find this op is very
> slowly。 I find the osd which contain bucket-obj。and see the
> “bucket_prepare_op”by dump_historic_ops :
> { "description": "osd_op(client.4742.0:87613 .dir.default.4243.3 [call
> rgw.bucket_prepare_op] 3.3670fe74 e317)",
> "received_at": "2014-06-30 13:35:55.409597",
> "age": "51.148026",
> "duration": "4.130137",
> "type_data": [
> "commit sent; apply or cleanup",
> { "client": "client.4742",
> "tid": 87613},
> [
> { "time": "2014-06-30 13:35:55.409660",
> "event": "waiting_for_osdmap"},
> { "time": "2014-06-30 13:35:55.409669",
> "event": "queue op_wq"},
> { "time": "2014-06-30 13:35:55.896766",
> "event": "reached_pg"},
> { "time": "2014-06-30 13:35:55.896793",
> "event": "started"},
> { "time": "2014-06-30 13:35:55.896796",
> "event": "started"},
> { "time": "2014-06-30 13:35:55.899450",
> "event": "waiting for subops from [40,43]"},
> { "time": "2014-06-30 13:35:55.899757",
> "event": "commit_queued_for_journal_write"},
> { "time": "2014-06-30 13:35:55.899799",
> "event": "write_thread_in_journal_buffer"},
> { "time": "2014-06-30 13:35:55.899910",
> "event": "journaled_completion_queued"},
> { "time": "2014-06-30 13:35:55.899936",
> "event": "journal first callback"},
> { "time": "2014-06-30 13:35:55.899944",
> "event": "queuing ondisk"},
> { "time": "2014-06-30 13:35:56.142104",
> "event": "sub_op_commit_rec"},
> { "time": "2014-06-30 13:35:56.176950",
> "event": "sub_op_commit_rec"},
> { "time": "2014-06-30 13:35:59.535301",
> "event": "op_commit"},
> { "time": "2014-06-30 13:35:59.535331",
> "event": "commit_sent"},
> { "time": "2014-06-30 13:35:59.539723",
> "event": "op_applied"},
> { "time": "2014-06-30 13:35:59.539734",
> "event": "done"}]]},
>
> so why from "journaled_completion_queued" to "op_commit" is very slowly, and
> what happened?
> thanks
>
> baijia...@126.com
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