Apparently a previous invocation of mhonarc aborted abnormally
and left the lock file. You will need to manually delete the file
to get things going again.
Hmm, could this happen if multiple instantiations of mhonarc are trying to
write to the archive at the same time?
Maybe. If your mail traffic is heavy, to many mhonarc processes could
be competing to access the archive. You either need to adjust the
LOCKTRIES and LOCKDELAY resources, or do batch updates of the archive
via a cron job. I believe several users do this over automatic archive
updates because of heavy traffic.
Doing batch updates will also reduce overall CPU load.
Any issues with the archives being written to an NFS partition?
It could slow things down depending on your network load. MHonArc
does not use flock/lockf so NFS should be okay. The mhonarc.lck
file (which is actually a directory) seems to work for all
platforms and avoids NFS limitations.