- zone_reclaim_mode defaults to the wrong value for database servers, 1, on some Linux distributions, including Red Hat.
- This default will both cause Linux to fail to use all available RAM for caching, and throttle writes.
- If you're running PostgreSQL, make sure that zone_reclaim_mode is set to 0.
Saturday, August 25, 2012
Wrong defaults for zone_reclaim_mode on Linux
My coworker Jeff Frost just published a writeup on "zone reclaim mode" in Linux, and how it can be a problem. Since his post is rather detailed, I wanted to give a "do this" summary: