Patroni
Benchmarking etcd v2.2.0
Performance measures for etcd v2.2.0
Physical Machines
GCE n1-highcpu-2 machine type
-
1x dedicated local SSD mounted as etcd data directory
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1x dedicated slow disk for the OS
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1.8 GB memory
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2x CPUs
etcd Cluster
3 etcd 2.2.0 members, each runs on a single machine.
Detailed versions:
etcd Version: 2.2.0 Git SHA: e4561dd Go Version: go1.5 Go OS/Arch: linux/amd64
Testing
Bootstrap another machine, outside of the etcd cluster, and run the hey HTTP benchmark tool with a connection reuse patch to send requests to each etcd cluster member. See the benchmark instructions for the patch and the steps to reproduce our procedures.
The performance is calculated through results of 100 benchmark rounds.
Performance
Single Key Read Performance
| key size in bytes | number of clients | target etcd server | average read QPS | read QPS stddev | average 90th Percentile Latency (ms) | latency stddev |
|---|---|---|---|---|---|---|
64 |
1 |
leader only |
2303 |
200 |
0.49 |
0.06 |
64 |
64 |
leader only |
15048 |
685 |
7.60 |
0.46 |
64 |
256 |
leader only |
14508 |
434 |
29.76 |
1.05 |
256 |
1 |
leader only |
2162 |
214 |
0.52 |
0.06 |
256 |
64 |
leader only |
14789 |
792 |
7.69 |
0.48 |
256 |
256 |
leader only |
14424 |
512 |
29.92 |
1.42 |
64 |
64 |
all servers |
45752 |
2048 |
2.47 |
0.14 |
64 |
256 |
all servers |
46592 |
1273 |
10.14 |
0.59 |
256 |
64 |
all servers |
45332 |
1847 |
2.48 |
0.12 |
256 |
256 |
all servers |
46485 |
1340 |
10.18 |
0.74 |
Single Key Write Performance
| key size in bytes | number of clients | target etcd server | average write QPS | write QPS stddev | average 90th Percentile Latency (ms) | latency stddev |
|---|---|---|---|---|---|---|
64 |
1 |
leader only |
55 |
4 |
24.51 |
13.26 |
64 |
64 |
leader only |
2139 |
125 |
35.23 |
3.40 |
64 |
256 |
leader only |
4581 |
581 |
70.53 |
10.22 |
256 |
1 |
leader only |
56 |
4 |
22.37 |
4.33 |
256 |
64 |
leader only |
2052 |
151 |
36.83 |
4.20 |
256 |
256 |
leader only |
4442 |
560 |
71.59 |
10.03 |
64 |
64 |
all servers |
1625 |
85 |
58.51 |
5.14 |
64 |
256 |
all servers |
4461 |
298 |
89.47 |
36.48 |
256 |
64 |
all servers |
1599 |
94 |
60.11 |
6.43 |
256 |
256 |
all servers |
4315 |
193 |
88.98 |
7.01 |
Performance Changes
-
Because etcd now records metrics for each API call, read QPS performance seems to see a minor decrease in most scenarios. This minimal performance impact was judged a reasonable investment for the breadth of monitoring and debugging information returned.
-
Write QPS to cluster leaders seems to be increased by a small margin. This is because the main loop and entry apply loops were decoupled in the etcd raft logic, eliminating several blocks between them.
-
Write QPS to all members seems to be increased by a significant margin, because followers now receive the latest commit index sooner, and commit proposals more quickly.