Forum OpenACS Development: Re: performance hint for busy sites with linux

Posted by Eduardo Santos on
Hi Gustaf,

Thank you very much for sharing this with us. I would never think off such a thing.

I guess a good way to find out if this is hapenning to our system is to see if there are some queries taking longer than it should without any clear reason? Or maybe some other I/O operations being too slow?

Posted by Gustaf Neumann on
A good start is to grep for "longdb" in your error log and check for queries that are fast under normal conditions.

Another option in general is to switch to other file systems, especially with newer kernels. Here are some options tested with PostgreSQL 9 with some recent Linux kernels, using already data=writeback per default

One can see, ext3 or ext4 are not among the fastests for TPC-B with PostgreSQL. I would not recommend everybody to switch blindly. Sites with low db activity and traffic won't see any difference.