Hello Paul, thanks for your response/hints.
I discovered the following tool in the ceph source repository: https://github.com/ceph/ceph/blob/master/src/tools/histogram_dump.py The tool provides output based on the statistics mention by you: # ceph daemon osd.24 perf histogram dump|grep -P "op_.*_latency" "op_r_latency_out_bytes_histogram": { "op_w_latency_in_bytes_histogram": { "op_rw_latency_in_bytes_histogram": { "op_rw_latency_out_bytes_histogram": { cd /tmp wget https://raw.githubusercontent.com/ceph/ceph/master/src/tools/histogram_dump.py chmod +x histogram_dump.py Request size (bytes): 0 512 1k 2k 4k 8k 16k 32k 65k 131k 262k 524k 1M 2M 4M 8M 16M 33M 67M 134M 268M 536M 1G 2G 4G 8G 17G 34G 68G 137G 274G -1 511 1k 2k 4k 8k 16k 32k 65k 131k 262k 524k 1M 2M 4M 8M 16M 33M 67M 134M 268M 536M 1G 2G 4G 8G 17G 34G 68G 137G 274G Latency (usec): 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 : -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 : 99k 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100k : 199k 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 200k : 399k 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 400k : 799k 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 800k : 1M 0 0 0 0 0 4 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1M : 3M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3M : 6M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6M : 12M 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12M : 25M 0 0 0 0 0 *5* 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 25M : 51M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 51M : 102M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 102M : 204M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 204M : 409M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 409M : 819M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 819M : 1G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1G : 3G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3G : 6G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6G : 13G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13G : 26G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26G : 52G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 52G : 104G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 104G : 209G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 209G : 419G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 419G : 838G 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 838G : 1T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1T : 3T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3T : 6T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6T : 13T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 13T : 26T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26T : 53T 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 53T : Probably this script is a good basis for writing my own specialized tool .... This might be a good option for detailed analysis. In a first step i just would like to have two simple KPIs which describe a average/aggregated write/read latency of these statistics. Are there tools/other functionalities which provide this in a simple way? Regards Marc Am 11.07.2018 um 18:42 schrieb Paul Emmerich: > Hi, > > from experience: commit/apply_latency are not good metrics, the only > good thing about them is that they are really easy to track. > But we have found them to be almost completely useless in the real world. > > We track the op_*_latency metrics from perf dump and found them to be > very helpful, they are more annoying to track due to their > format. The median OSD is a good indicator and so is the slowest OSD. > > Paul > > 2018-07-11 17:50 GMT+02:00 Marc Schöchlin <m...@256bit.org > <mailto:m...@256bit.org>>: > > Hello ceph-users and ceph-devel list, > > we got in production with our new shiny luminous (12.2.5) cluster. > This cluster runs SSD and HDD based OSD pools. > > To ensure the service quality of the cluster and to have a > baseline for > client latency optimization (i.e. in the area of deepscrub > optimization) > we would like to have statistics about the client interaction > latency of > our cluster. > > Which measures can be suitable to get such a "aggregated by > device_class" average latency KPI? > Also a percentile rank would be great (% amount of requests > serviced by > < 5ms, % amount of requests serviced by < 20ms, % amount of requests > serviced by < 50ms, ...) > > The following command provides a overview over the commit latency > of the > osds but no average latency and no information about the device_class. > > ceph osd perf -f json-pretty > > { > "osd_perf_infos": [ > { > "id": 71, > "perf_stats": { > "commit_latency_ms": 2, > "apply_latency_ms": 0 > } > }, > { > "id": 70, > "perf_stats": { > "commit_latency_ms": 3, > "apply_latency_ms": 0 > } > > Device class information can be extracted of "ceph df -f json-pretty". > > But building averages of averages not seems to be a good thing > .... :-) > > It seems that i can get more detailed information using the "ceph > daemon > osd.<nr> perf histogram dump" command. > This seems to deliver the percentile rank information in a good detail > level. > (http://docs.ceph.com/docs/luminous/dev/perf_histograms/ > <http://docs.ceph.com/docs/luminous/dev/perf_histograms/>) > > My questions: > > Are there tools to analyze and aggregate these measures for a > group of OSDs? > > Which measures should i use as a baseline for client latency > optimization? > > What is the time horizon of these measures? > > I sometimes see messages like this in my log. > This seems to be sourced in deep scrubbing. How can find the > source/solution of this problem? > > 2018-07-11 16:58:55.064497 mon.ceph-mon-s43 [INF] Cluster is now > healthy > 2018-07-11 16:59:15.141214 mon.ceph-mon-s43 [WRN] Health check > failed: 4 > slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:25.037707 mon.ceph-mon-s43 [WRN] Health check > update: 9 > slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:30.038001 mon.ceph-mon-s43 [WRN] Health check update: > 23 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:35.210900 mon.ceph-mon-s43 [WRN] Health check update: > 27 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:45.038718 mon.ceph-mon-s43 [WRN] Health check update: > 29 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:50.038955 mon.ceph-mon-s43 [WRN] Health check update: > 39 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 16:59:55.281279 mon.ceph-mon-s43 [WRN] Health check update: > 44 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 17:00:00.000121 mon.ceph-mon-s43 [WRN] overall > HEALTH_WARN 12 > slow requests are blocked > 32 sec > 2018-07-11 17:00:05.039677 mon.ceph-mon-s43 [WRN] Health check update: > 12 slow requests are blocked > 32 sec (REQUEST_SLOW) > 2018-07-11 17:00:09.329897 mon.ceph-mon-s43 [INF] Health check > cleared: > REQUEST_SLOW (was: 12 slow requests are blocked > 32 sec) > 2018-07-11 17:00:09.329919 mon.ceph-mon-s43 [INF] Cluster is now > healthy > > Regards > Marc > > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com <mailto:ceph-users@lists.ceph.com> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > <http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com> > > > > > -- > Paul Emmerich > > Looking for help with your Ceph cluster? Contact us at https://croit.io > > croit GmbH > Freseniusstr. 31h > 81247 München > www.croit.io <http://www.croit.io> > Tel: +49 89 1896585 90
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