Hi! Regarding my previous email (nsd3 fills disk, "out of mem" during patching) I found out that this was caused by a concurrent zone transfer. This race conditions seems to require 3 times the typical nsd memory size: 1. the currently serving nsd process 2. the newly span nsd process which read the new db files 3. the nsd-patch or the zonec utility Is there a method to prevent zone transfers (and the subsequent nsd reload) during patching? Or prevent patching during zone transfer? Further I wonder if it is always safe to patch as during patching the ixfr.db and nsd.db may be deleted. I suspect there may be race conditions for example if their is a concurrent transfer and nsd itself manipulates the ixfr.db file and the xfrd.state file. Or the transfer may manipulate the ixfr.db file nsd-patch reads from it. Thanks Klaus