Re: cache sync ioctl, freezes

[Brian Buhrow <buhrow%nfbcal.org@localhost>]

	hello greg.  A couple of years ago I ran into horrible performance issues using zvols as
disks for vm's on FreeBSD.  Some web searching revealed that zvols as disks on zfs under any
OS, including Solaris, Linux and FreeBSD was, as a practical matter, a very bad idea because of
the very way ZFS is designed to operate.  Unfortunately, I don't have the reference where I
found the paper describing all of this detail.
The upshot of this was that I converted to using files as disks inside ZFS anf found performance
to be orders of magnetude better.
	Unfortunately, I've not tried runing ZFS on NetBSD for some time, so I can't say how well
it does there.

-thanks
-Brian