Hi,

I recently did a manual upgrade of a NetBSD installation on an
old PC with a slow disk.  Since the distribution sets contain
lots of relatively small files, re-mounting the file systems with
the "async" option before unpacking helped quite a bit on the
speed of the upgrade.  After booting the new kernel single-user
and setting it up for the upgrade I did

# mount -u -o async /

and similarly for /usr.  After the upgrade I did

# sync
# mount -u -o noasync /

and similarly for /usr.

Where I live power failures are relatively rare, so I found the
risk of doing this acceptable.  Your mileage may vary.

This should however be relatively "safe" to do on a fresh
install, perhaps it's an idea for sysinst?  Just need to remember
the sync and the remount, though...

- Havard