Subject: Re: ffs_valloc: dup alloc
To: Stephen Borrill <netbsd@precedence.co.uk>
From: Greywolf <greywolf@starwolf.com>
List: port-i386
Date: 02/26/2002 22:35:06
On Tue, 26 Feb 2002, Stephen Borrill wrote:

# > On Mon, Feb 25, 2002 at 05:22:16PM +0000, Christos Zoulas wrote:
# > A simple way to avoid this problem is to increase your filesystem
# > blocksize; then you won't *have* to use triply-indirect blocks (thank
# > goodness).
#
# That sounds like a good plan. The current filesystem block size is 8192 and
# the partition in question has a size of 37846368 512-byte sectors. What's the
# rule of thumb to calculate the minimum block size that will stop
# triple-indirects given such parameters?

This does not sound like a good plan.  If triply indirect blocks don't
work then the fundaments of the FFS are broken and need to be fixed,
not worked around or swept under the rug.

If you can get around triple indirection, yes, it's a perf win, but
don't leave it broken.

# Dr. Stephen Borrill

				--*greywolf;
--
NetBSD: The Last Bastion of the true UNIX Religion.