In T244340 we discussed about introducing an onhost memcached in order to further speed up our cache fetches.
In this test we will install memcached on mwdebug1001 on localhost:1120 and add and tell mcrouter to use it using the WarmupRoute. Additionally we will add a prometheus exporter.
Test scenario:
**Servers:** mwdebug1001 (with onhost memcached), & mwdebug1002
**Clients:** mwdebug2001, mwbug2001
We will run the same subset of URLs against both servers
Testing in production:
Manually install a mcrouter config on mw2271 (appserver) and use the following config:
``` {
"aliases": [
"/codfw/mw/"
],
"route": {
"type": "OperationSelectorRoute",
"operation_policies": {
"get": {
"type": "WarmUpRoute",
"cold": "PoolRoute|onhost",
"warm":
{
"failover": "PoolRoute|gutter",
"failover_errors": [
"tko"
],
"failover_exptime": 600,
"normal": "PoolRoute|codfw",
"type": "FailoverWithExptimeRoute"
},
"exptime": 10
}
},
"default_policy": {
"failover": "PoolRoute|gutter",
"failover_errors": [
"tko"
],
"failover_exptime": 600,
"normal": "PoolRoute|codfw",
"type": "FailoverWithExptimeRoute"
}
}
},```
In other words:
* All GETs (but not /*/mw-wan) are first looked up in the onhost memcached (cold) and if not found are fetched from our memcached cluster (warm) and are added (ADD) back in the onhost memcached with a max TTL of 10.
* All other commands are routed to the memcached cluster or the gutter pool
dashboard: https://grafana.wikimedia.org/d/jI1SNdFMz/xxxx-effie-compare-mediawiki-hosts?orgId=1