From owner-freebsd-hackers Sun Feb 9 16:51:46 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id QAA24150 for hackers-outgoing; Sun, 9 Feb 1997 16:51:46 -0800 (PST) Received: from whistle.com (s205m131.whistle.com [207.76.205.131]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id QAA24139 for ; Sun, 9 Feb 1997 16:51:41 -0800 (PST) Received: (from smap@localhost) by whistle.com (8.7.5/8.6.12) id QAA17889; Sun, 9 Feb 1997 16:51:09 -0800 (PST) Received: from alpo.whistle.com(207.76.205.1) by whistle.com via smap (V1.3) id sma017887; Sun Feb 9 16:50:48 1997 Received: from current1.whistle.com (current1.whistle.com [207.76.205.22]) by alpo.whistle.com (8.8.5/8.8.4) with SMTP id QAA12738; Sun, 9 Feb 1997 16:49:13 -0800 (PST) Message-ID: <32FE7015.2F1CF0FB@whistle.com> Date: Sun, 09 Feb 1997 16:47:17 -0800 From: Julian Elischer Organization: Whistle Communications X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386) MIME-Version: 1.0 To: Joerg Wunsch CC: FreeBSD hackers , Thomas David Rivers Subject: Re: Copious information on panic: ffs_valloc: dup alloc - IDEAS??? References: <199702091818.NAA23739@lakes.water.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk J Wunsch wrote: > > As Thomas David Rivers wrote: > > > You're saying the code in newfs.c that sets NTRACKS to 1 and > > NSECTORS to 4096 would be changed. > > Yes, to e.g. 2 * 2048 instead. It's a mileage number only anyway, > since Poul found out (experimentally) that it just works better than > any (un)real number on today's zone-bit recorded and large cache > disks. > > > If this is so, doesn't that mean that everyone is using a file system > > that is questionable. Aren't inode reads/writes going to the wrong > > places (albeit consistently?) > > I'm no filesystem expert at all, but this seems to be the case. The > failure picture matches consistently with the reported MFS troubles > (including mine), and it's probably also responsible for some other > panic PRs you could find in the GNATS database. > > -- > Kirk suggested setting the number of heads to 1 to turn off the "selelct a nearby head" code.. if you make it have 2 heads, this code will be enabled again and we'll lose the effect.. it pessimise the accesses by switching to a differnt head that it thinks has a nearby free block.. in the case of 2 heads (as suggested) this is actually likely to be "NOT NEARBY" and we will lose you could HEAR the difference when we went to 1 head..