We currently have dbstore servers supporting multi-instance with systemd running on Debian Stretch
We need support for multi-instance on the core servers now.
To do that we have some paths that we could follow:
~~Jessie + 10.0 + support for init.d with mysqld_multi ~~
~~Jessie + 10.1~~
**Stretch + 10.1 (only on those hosts).**
Some work has already been done and db2084 is being used as a testing host: https://gerrit.wikimedia.org/r/#/c/384452/
The idea is to use 8 hosts to serve all the recentchanges services across all the core shards.
Splitting them across them so we can have redundancy:
codfw:
~~[] `db2092 (B8): will not be done, because we don't need special replicas on s3 https://gerrit.wikimedia.org/r/394573 ~~
[x] `db2091 (A8): s2, s4` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389679/)
[x] `db2086 (B1): s8, s7` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389676/)
[x] `db2089 (A3): s6, s5` (will start replicating s5 as s8 is still not split) (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389674/)
[x] `db2087 (C1): s6, s7` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389454/)
[x] `db2088 (D1): s1, s2` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389434/)
[x] `db2084 (D6): s4, s5` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/386810/)
[x] `db2085 (A6): s1, s8` (pooled initially as s3, s8 in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/389413/, depooled and pooled again as s1, s8 https://gerrit.wikimedia.org/r/394573)
eqiad
[x] `db1099 (B2): s1, s8` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/394008/)
[x] `db1103 (A3): s2, s4` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/390947/)
[x] `db1101 (C2): s8, s7` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/392797/)
[] `db1096 (A6): s6, s5`
[] `db1098 (B5): s6, s7`
[x] `db1105 (C3): s1, s2` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/391161/)
[x] `db1097 (D1): s4. s5` (pooled in mediawiki-config: https://gerrit.wikimedia.org/r/#/c/393175/)