[nsd-users] NSD database memory usage

[Antti Ristimäki]

Hello,

We have an installation, where NSD (version 4.1.19) acts as a hidden master for the public DNS servers. NSD has only one large zone configured and the zone is periodically signed every 20 minutes and after each re-signing, "nsd-control reload <zone>" is given so that the NSD process reloads the new zone from the zonefile and notifies the slaves. However, we noticed that the database memory usage increases after every reload, finally resulting in memory allocation failure. We stat the memory usage by running "nsd-control stats_noreset" every minute and in the graph [1] one can see the increase in size.db.mem after each reload. We don't see similar behaviour with for example xfrd process memory usage.

We have worked around the issue by restarting the NSD process periodically, but do you have any ideas about the possible root cause and a more long term solution?

[1] http://nxdomain.fi/NSD_db_mem.png

Regards,

Antti