Physical machine

GCE n1-standard-2 machine type

• 1x dedicated local SSD mounted under /var/lib/etcd
• 1x dedicated slow disk for the OS
• 7.5 GB memory
• 2x CPUs

etcd

etcd Version: 2.2.0-rc.0+git
Git SHA: 103cb5c
Go Version: go1.5
Go OS/Arch: linux/amd64

Testing

Start 3-member etcd cluster, each of which uses 2 cores.

The length of key name is always 64 bytes, which is a reasonable length of average key bytes.

Memory Maximal Usage

• etcd may use maximal memory if one follower is dead and the leader keeps sending snapshots.
• max RSS is the maximal memory usage recorded in 3 runs.

  value bytes	key number	data size(MB)	max RSS(MB)	max RSS/data rate on leader
  128	50000	6	433	72x
  128	100000	12	659	54x
  128	200000	24	1466	61x
  1024	50000	48	1253	26x
  1024	100000	96	2344	24x
  1024	200000	192	4361	22x

Data Size Threshold

• When etcd reaches data size threshold, it may trigger leader election easily and drop part of proposals.
• For most cases, the etcd cluster should work smoothly if it doesn’t hit the threshold. If it doesn’t work well due to insufficient resources, decrease its data size.

  value bytes	key number limitation	suggested data size threshold(MB)	consumed RSS(MB)
  128	400K	48	2400
  1024	300K	292	6500