Hi guys, 

Could someone explain what's the new perf stats show and if the numbers are 
reasonable on my cluster? 

I am concerned about the high fs_commit_latency, which seems to be above 150ms 
for all osds. I've tried to find the documentation on what this command 
actually shows, but couldn't find anything. 

I am using 3TB sas drives with 4 osd journals on each ssd. Are the numbers 
below reasonable for a fairly idle ceph cluster (osd utilisation below 10% on 
average)? 

# ceph osd perf 
osdid fs_commit_latency(ms) fs_apply_latency(ms) 
0 192 4 
1 265 4 
2 116 1 
3 125 2 
4 166 1 
5 209 3 
6 184 6 
7 142 2 
8 209 1 
9 166 1 
10 216 1 
11 308 3 
12 150 2 
13 125 1 
14 175 2 
15 142 2 
16 150 4 


when the cluster get's a bit busy (osd utilisation below 50% on average) I see: 

# ceph osd perf 
osdid fs_commit_latency(ms) fs_apply_latency(ms) 
0 551 11 
1 284 25 
2 517 41 
3 492 14 
4 625 13 
5 309 26 
6 650 9 
7 517 21 
8 634 25 
9 784 32 
10 392 7 
11 501 8 
12 602 12 
13 467 14 
14 476 36 
15 451 11 
16 383 21 



Thanks 

Andrei 
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