Database performance tuning

I have an application that currently runs hosted on, using their MySQL server. I want to move the application to my Linode 96. At first, I tried installing PostgreSQL and porting the application. The performance was abysmal. A typical run which takes 1:05 on Gradwell took 25:15. I put it on my home server (two Athlon MP1800+ processors, 1024Mb of RAM) and on PostgreSQL it runs in 7:45. Still too slow. So I tried it on my home server with MySQL, and it ran in 0:32.

So I decided to try it on the Linode with MySQL. And the performance sucks sucks suck. It took 42:01.

I think the application itself is a bit big, "top" shows it as 12m. But there's got to be some way to tune MySQL to fit well on a 96Mb linode. Any hints?

7 Replies

Have you tweaked MySQL via my.cnf? Sometimes that helps performance


Have you tweaked MySQL via my.cnf? Sometimes that helps performance

Tweaked what? Any suggestions what parameters to tune, and what values work on a 96?

Theres a file in /etc called my.cnf which contains the directives for MySQL. Caker made a my.cnf file designed for low memory at Besides that, you should think about a memory upgrade, purchased via the LPM in the extras section.

Linode Staff

There are two things I'd watch in two windows as queries are being ran:

watch -n1 cat /proc/io_status


vmstat 1

For the former, if you see tokens go negative, you've hit the limiter – most likely due to swap thrashing, which the second command will show you (si and so).

Some of mysql's default settings will eat up a decent chunk of RAM, and depending on other things you've got running you might be swap thrashing.


I'm not seeing much activity in the io_tokens - hovering around 400000 or just slightly below. But it's still damn slow. Using the previous poster's link to that my.cnf file, I tried those values (and restarted mysqld of course) and it's no faster.

It's amazingly annoying - I took the database dumps and the code directly from Gradwell to here, and yet on Gradwell it takes 1:14 and here it takes 43:54.

Linode Staff

If this is a restore of a previous database, did you carry over all the indexes?


Linode Staff

Just a follow-up post – Thanks to I noticed this: … -the-table">

Keep in mind that Xen is coming, which will greatly improve performance. Compare the following kernel build times:

Host(noXen): 5m5.993s

dom0 (Xen host): 5m19.758s

domU(Xenode): 5m49.133s

UML(Linode): 15m24.464s



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