I create a rbd pool using only two SATA SSDs(one for data, another for
database,WAL), and set the replica size 1.
After that, I setup a fio test on Host same with the OSD placed. I found
the latency is hundreds micro-seconds(sixty micro-seconds for the raw
SATA SSD ).
The fio outpus:
m-seqwr-004k-001q-001j: (groupid=0, jobs=1): err= 0: pid=46: Wed Dec 15
14:05:32 2021
write: IOPS=794, BW=3177KiB/s (3254kB/s)(559MiB/180002msec); 0 zone
resets
slat (usec): min=4, max=123, avg=22.30, stdev= 9.18
clat (usec): min=630, max=16977, avg=1232.89, stdev=354.67
lat (usec): min=639, max=17009, avg=1255.19, stdev=358.99
clat percentiles (usec):
| 1.00th=[ 709], 5.00th=[ 775], 10.00th=[ 824], 20.00th=[ 906],
| 30.00th=[ 1074], 40.00th=[ 1172], 50.00th=[ 1237], 60.00th=[ 1303],
| 70.00th=[ 1369], 80.00th=[ 1450], 90.00th=[ 1565], 95.00th=[ 1663],
| 99.00th=[ 2606], 99.50th=[ 3261], 99.90th=[ 3785], 99.95th=[ 3949],
| 99.99th=[ 6718]
bw ( KiB/s): min= 1928, max= 5048, per=100.00%, avg=3179.54,
stdev=588.79, samples=360
iops : min= 482, max= 1262, avg=794.76, stdev=147.20,
samples=360
lat (usec) : 750=2.98%, 1000=22.41%
lat (msec) : 2=73.38%, 4=1.18%, 10=0.04%, 20=0.01%
cpu : usr=2.69%, sys=1.78%, ctx=145218, majf=0, minf=2
IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%,
>=64=0.0%
submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%,
>=64=0.0%
complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%,
>=64=0.0%
issued rwts: total=0,142985,0,0 short=0,0,0,0 dropped=0,0,0,0
latency : target=0, window=0, percentile=100.00%, depth=1
Parts of the OSD' perf status:
"state_io_done_lat": {
"avgcount": 151295,
"sum": 0.336297058,
"avgtime": 0.000002222
},
"state_kv_queued_lat": {
"avgcount": 151295,
"sum": 18.812333051,
"avgtime": 0.000124342
},
"state_kv_commiting_lat": {
"avgcount": 151295,
"sum": 64.555436175,
"avgtime": 0.000426685
},
"state_kv_done_lat": {
"avgcount": 151295,
"sum": 0.130403628,
"avgtime": 0.000000861
},
"state_deferred_queued_lat": {
"avgcount": 148,
"sum": 215.726286547,
"avgtime": 1.457610044
},
... ...
"op_w_latency": {
"avgcount": 151133,
"sum": 130.134246667,
"avgtime": 0.000861057
},
"op_w_process_latency": {
"avgcount": 151133,
"sum": 125.301196872,
"avgtime": 0.000829079
},
"op_w_prepare_latency": {
"avgcount": 151133,
"sum": 29.892687947,
"avgtime": 0.000197790
},
Is it reasonable for the benchmark test case? And how to improve it?
It's really NOT friendly for single thread.
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