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Date: Mon, 27 Mar 1995 18:57:45 +1000
From: Stephen McKay <syssgm@devetir.qld.gov.au>
Message-Id: <199503270857.SAA07337@orion.devetir.qld.gov.au>
To: hackers@FreeBSD.org
cc: terry@cs.weber.edu (Terry Lambert)
Subject: Valid uses of async mounts (was: Why IDE is bad)
Sender: hackers-owner@FreeBSD.org
Precedence: bulk

terry@cs.weber.edu (Terry Lambert) wrote:
>> >>    It should do what the manual page says it does, which is to force
>> >> all I/O to the filesystem to be done asynchronously.
>
>The use of "async" in this context doesn't "make no sense on local disks",
>it just "makes no sense period".

I have a short program which enables "delayed I/O" on filesystems under SunOS.
This looks like the same thing as async is supposed to do for FreeBSD.  It
is claimed to be useful when doing file system restores, giving "about a 500%
increase in the speed of the restore".

>The only exception to that is a tmpfs, which is clean on each boot anyway
>and might as well be remkfs'ed as anything else to get it clean.

It is also advertised as being "good for /tmp giving most of the benefits of
tmpfs without the problems".  You are supposed to insert "fsck -y /tmp"
somewhere before the "fsck -p" in /etc/rc to fix up after nasty crashes.

>I don't think "async" should be an option, and if it must stay, at
>least say "DANGER! MOUNTING /dev/whazzit ASYNC!".

Surely it should be "DANGER, WILL ROBINSON!" :-)

Stephen.