What's it all about, Alfie?

When faced with the idea that CouchDB might be running low on sockets (file handles), I decided to do a little digging into the CentOS 5 configuration, and see what I could do. Turns out it wasn't all that hard, and I got immediate results. The first thing is to up the hard and soft limits on the file handles in /etc/security/limits.conf for the couchdb user:

  couchdb  soft  nofile  32768
  couchdb  hard  nofile  60000

then simply restart CouchDB. Look at the process limits by:

  $ cat /proc/1234/limits

where 1234 is the pid of the erlang 'beam' process, and see what it says. You are also going to need to tell Erlang about the number of file handles in the /usr/local/etc/default/couchdb file:

  export ERL_MAX_PORTS=32768
  export ERL_FLAGS="+A 8"

The second little bit there is to allow 8 threads in Erlang to process disk updates. This multi-threaded filesystem access isn't on be default for Erlang, so if you're on a big box with lots of cores, it makes a lot of sense to turn it on.

With these, you have CouchDB running about as well as you can get. The rest is up to you.

This entry was posted on Friday, November 9th, 2012 at 9:33 am and is filed under Coding, Cube Life, Open Source Software. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.