What optimizations do you use for mysql with a lot of databases?

Question

MySQL

For example mysql with 5-10 thousand databases.
Now mysql version 5.1 does it make sense to migrate to 5.5, will it add performance?
The databases are quite small, but there are a lot of them and there are about 20 tables inside each.
There is a tint when restarting and sometimes when executing the show databases command;
Do not suggest changing the data storage method, there is no point in doing sharding yet, since the load is not large.

Answer 1

If the databases are not related to each other, then I would just split them into several independent mysql processes. They can also be restarted one by one independently.
The only possible problem is that the software that connects to mysql must know about it (different socket files, ports, IP).

Answer 2

Try to increase
table_cache a lot
More here
dev.mysql.com/doc/refman/5.0/en/table-cache.html

Answer 3

>whether migration on 5.5
has sense. they did a lot of stuff there. still it makes sense to look at Percona server.

Answer 4

Partially helped to mount the system with the options
noatime,nodiratime,async,commit=1,data=journal
No other effective optimizations yet found