Ticket #102 (closed defect: fixed)
disk traffic huge with ~200,000 records in MUA DB
|Reported by:||chris.franks@…||Owned by:||Phil Smart|
|Keywords:||disk io caching||Cc:||richard.james@…|
MUA setup using MySQL on localhost.
Disk traffic is ~50,000KB/s (our mailing list server is doing under 250 KB/s - 200x less).
System still has free RAM. But is caching very quickly (upto 2.5g in cache, down to roughly 500m in 5 seconds, and back up again).
This is making everything slow (i.e. user input at the console can take 5/6seconds to appear, the raptorwebd, when its running is very slow). We think this is due to disk latency (high IO wait value in the CPU monitoring graph).
I followed http://iam.cf.ac.uk/trac/RAPTOR/ticket/85 initially, thinking this was a JVM memory issue but its still happening, with a limit of 512M (and only the MUA and database server running).
I'll attaced some munin monitoring graphs for the machine - is this a common problem with MySQL? It seems to run ok when we clear the tables but we get back up to ~160,000 records in about a week).
Any pointers for speeding things up would be appreciated.