Hi,
We are trying to reduce the peering processing latency, since it may
block front io.
in our experiment, we kill certain osd and bring it back after a very
short time. We checked performance counters as below:
"peering_latency": {
"avgcount": 52,
"sum": 52.435308773,
"avglat": 1008.371323
},
"getinfo_latency": {
"avgcount": 52,
"sum": 3.525831625,
"avglat": 67.804454
},
"getlog_latency": {
"avgcount": 46,
"sum": 0.255325943,
"avglat": 5.550564
},
"getmissing_latency": {
"avgcount": 46,
"sum": 0.000877735,
"avglat": 0.019081
},
"waitupthru_latency": {
"avgcount": 46,
"sum": 48.652836368,
"avglat": 1057.670356
}
as shown, average peering latency is 1008ms, most of them are consumed
by "waitupthru_latency". By looking at the codes, i am not quite
understand this part. Can anyone explain this part especially why it
takes such long time in this stage?
I also noticed there's some description regarding "fast peering" on
http://tracker.ceph.com/projects/ceph/wiki/Osd_-_Faster_Peering
is this still ongoing or stale?
I am appreciated for any kind reply.
Thanks,
Sheng
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