Hello everyone,
I am running a number of parallel benchmark tests against the cluster that should be ready to go to production.
I enabled prometheus to monitor various information and while cluster stays healthy through the tests with no errors or slow requests,
I noticed an apply / commit latency jumping between 40 - 600 ms on multiple SSDs. At the same time op_read and op_write are on average below 0.25 ms in the worth case scenario.
I am running nautilus 14.2.2, all bluestore, no separate NVME devices for WAL/DB, 6 SSDs per node(Dell PowerEdge R440) with all drives Seagate Nytro 1551, osd spread across 6 nodes, running in
containers. Each node has plenty of RAM with utilization ~ 25 GB during the benchmark runs.
Here are benchmarks being run from 6 client systems in parallel, repeating the test for each block size in <4k,16k,128k,4M>.
On rbd mapped partition local to each client:
fio --name=randrw --ioengine=libaio --iodepth=4 --rw=randrw --bs=<4k,16k,128k,4M> --direct=1 --size=2G --numjobs=8 --runtime=300 --group_reporting --time_based --rwmixread=70
On mounted cephfs volume with each client storing test file(s) in own sub-directory:
fio --name=randrw --ioengine=libaio --iodepth=4 --rw=randrw --bs=<4k,16k,128k,4M> --direct=1 --size=2G --numjobs=8 --runtime=300 --group_reporting --time_based --rwmixread=70
dbench -t 30 30
Could you please let me know if huge jump in applied and committed latency is justified in my case and whether I can do anything to improve / fix it. Below is some additional cluster info.
Thank you,
root@storage2n2-la:~# podman exec -it ceph-mon-storage2n2-la ceph osd df
ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META AVAIL %USE VAR PGS STATUS
6 ssd 1.74609 1.00000 1.7 TiB 93 GiB 92 GiB 240 MiB 784 MiB 1.7 TiB 5.21 0.90 44 up
12 ssd 1.74609 1.00000 1.7 TiB 98 GiB 97 GiB 118 MiB 906 MiB 1.7 TiB 5.47 0.95 40 up
18 ssd 1.74609 1.00000 1.7 TiB 102 GiB 101 GiB 123 MiB 901 MiB 1.6 TiB 5.73 0.99 47 up
24 ssd 3.49219 1.00000 3.5 TiB 222 GiB 221 GiB 134 MiB 890 MiB 3.3 TiB 6.20 1.07 96 up
30 ssd 3.49219 1.00000 3.5 TiB 213 GiB 212 GiB 151 MiB 873 MiB 3.3 TiB 5.95 1.03 93 up
35 ssd 3.49219 1.00000 3.5 TiB 203 GiB 202 GiB 301 MiB 723 MiB 3.3 TiB 5.67 0.98 100 up
5 ssd 1.74609 1.00000 1.7 TiB 103 GiB 102 GiB 123 MiB 901 MiB 1.6 TiB 5.78 1.00 49 up
11 ssd 1.74609 1.00000 1.7 TiB 109 GiB 108 GiB 63 MiB 961 MiB 1.6 TiB 6.09 1.05 46 up
17 ssd 1.74609 1.00000 1.7 TiB 104 GiB 103 GiB 205 MiB 819 MiB 1.6 TiB 5.81 1.01 50 up
23 ssd 3.49219 1.00000 3.5 TiB 210 GiB 209 GiB 168 MiB 856 MiB 3.3 TiB 5.86 1.01 86 up
29 ssd 3.49219 1.00000 3.5 TiB 204 GiB 203 GiB 272 MiB 752 MiB 3.3 TiB 5.69 0.98 92 up
34 ssd 3.49219 1.00000 3.5 TiB 198 GiB 197 GiB 295 MiB 729 MiB 3.3 TiB 5.54 0.96 85 up
4 ssd 1.74609 1.00000 1.7 TiB 119 GiB 118 GiB 16 KiB 1024 MiB 1.6 TiB 6.67 1.15 50 up
10 ssd 1.74609 1.00000 1.7 TiB 95 GiB 94 GiB 183 MiB 841 MiB 1.7 TiB 5.31 0.92 46 up
16 ssd 1.74609 1.00000 1.7 TiB 102 GiB 101 GiB 122 MiB 902 MiB 1.6 TiB 5.72 0.99 50 up
22 ssd 3.49219 1.00000 3.5 TiB 218 GiB 217 GiB 109 MiB 915 MiB 3.3 TiB 6.11 1.06 91 up
28 ssd 3.49219 1.00000 3.5 TiB 198 GiB 197 GiB 343 MiB 681 MiB 3.3 TiB 5.54 0.96 95 up
33 ssd 3.49219 1.00000 3.5 TiB 198 GiB 196 GiB 297 MiB 1019 MiB 3.3 TiB 5.53 0.96 85 up
1 ssd 1.74609 1.00000 1.7 TiB 101 GiB 100 GiB 222 MiB 802 MiB 1.6 TiB 5.63 0.97 49 up
7 ssd 1.74609 1.00000 1.7 TiB 102 GiB 101 GiB 153 MiB 871 MiB 1.6 TiB 5.69 0.99 46 up
13 ssd 1.74609 1.00000 1.7 TiB 106 GiB 105 GiB 67 MiB 957 MiB 1.6 TiB 5.96 1.03 42 up
19 ssd 3.49219 1.00000 3.5 TiB 206 GiB 205 GiB 179 MiB 845 MiB 3.3 TiB 5.77 1.00 83 up
25 ssd 3.49219 1.00000 3.5 TiB 195 GiB 194 GiB 352 MiB 672 MiB 3.3 TiB 5.45 0.94 97 up
31 ssd 3.49219 1.00000 3.5 TiB 201 GiB 200 GiB 305 MiB 719 MiB 3.3 TiB 5.62 0.97 90 up
0 ssd 1.74609 1.00000 1.7 TiB 110 GiB 109 GiB 29 MiB 995 MiB 1.6 TiB 6.14 1.06 43 up
3 ssd 1.74609 1.00000 1.7 TiB 109 GiB 108 GiB 28 MiB 996 MiB 1.6 TiB 6.07 1.05 41 up
9 ssd 1.74609 1.00000 1.7 TiB 103 GiB 102 GiB 149 MiB 875 MiB 1.6 TiB 5.76 1.00 52 up
15 ssd 3.49219 1.00000 3.5 TiB 209 GiB 208 GiB 253 MiB 771 MiB 3.3 TiB 5.83 1.01 98 up
21 ssd 3.49219 1.00000 3.5 TiB 199 GiB 198 GiB 302 MiB 722 MiB 3.3 TiB 5.56 0.96 90 up
27 ssd 3.49219 1.00000 3.5 TiB 208 GiB 207 GiB 226 MiB 798 MiB 3.3 TiB 5.81 1.00 95 up
2 ssd 1.74609 1.00000 1.7 TiB 96 GiB 95 GiB 158 MiB 866 MiB 1.7 TiB 5.35 0.93 45 up
8 ssd 1.74609 1.00000 1.7 TiB 106 GiB 105 GiB 132 MiB 892 MiB 1.6 TiB 5.91 1.02 50 up
14 ssd 1.74609 1.00000 1.7 TiB 96 GiB 95 GiB 180 MiB 844 MiB 1.7 TiB 5.35 0.92 46 up
20 ssd 3.49219 1.00000 3.5 TiB 221 GiB 220 GiB 156 MiB 868 MiB 3.3 TiB 6.18 1.07 101 up
26 ssd 3.49219 1.00000 3.5 TiB 206 GiB 205 GiB 332 MiB 692 MiB 3.3 TiB 5.76 1.00 92 up
32 ssd 3.49219 1.00000 3.5 TiB 221 GiB 220 GiB 88 MiB 936 MiB 3.3 TiB 6.18 1.07 91 up
TOTAL 94 TiB 5.5 TiB 5.4 TiB 6.4 GiB 30 GiB 89 TiB 5.78
MIN/MAX VAR: 0.90/1.15 STDDEV: 0.30
root@storage2n2-la:~# podman exec -it ceph-mon-storage2n2-la ceph -s
cluster:
id: 9b4468b7-5bf2-4964-8aec-4b2f4bee87ad
health: HEALTH_OK
services:
mon: 3 daemons, quorum storage2n1-la,storage2n2-la,storage2n3-la (age 9w)
mgr: storage2n2-la(active, since 9w), standbys: storage2n1-la, storage2n3-la
mds: cephfs:1 {0=storage2n6-la=up:active} 1 up:standby-replay 1 up:standby
osd: 36 osds: 36 up (since 9w), 36 in (since 9w)
data:
pools: 3 pools, 832 pgs
objects: 4.18M objects, 1.8 TiB
usage: 5.5 TiB used, 89 TiB / 94 TiB avail
pgs: 832 active+clean
io:
client: 852 B/s rd, 15 KiB/s wr, 4 op/s rd, 2 op/s wr
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