From owner-freebsd-questions Fri Aug 30 22:36:57 1996 Return-Path: owner-questions Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id WAA21927 for questions-outgoing; Fri, 30 Aug 1996 22:36:57 -0700 (PDT) Received: from gdi.uoregon.edu (cisco-ts6-line16.uoregon.edu [128.223.150.46]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id WAA21921 for ; Fri, 30 Aug 1996 22:36:53 -0700 (PDT) Received: from localhost (dwhite@localhost) by gdi.uoregon.edu (8.7.5/8.6.12) with SMTP id WAA00350; Fri, 30 Aug 1996 22:36:45 -0700 (PDT) Date: Fri, 30 Aug 1996 22:36:44 -0700 (PDT) From: Doug White Reply-To: dwhite@resnet.uoregon.edu To: Scott Blachowicz cc: Eric Berenguier , questions@FreeBSD.ORG Subject: Re: FreeBSD 2.1.0 CRASH! In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-questions@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Thu, 29 Aug 1996, Scott Blachowicz wrote: > Doug White wrote: > > > Your swap is a bit small for your memory -- suggested is 2xmemory. > > Although running out of swap won't illicit a panic (usually), it would be > > something to consider. > > I've never really quite figured out that recommendation...unless you're > assuming that the system has the "right" amount of RAM to reasonably run all > the applications you want to run on it. In that case, the "2 x RAM" amount > is really an indirect way of saying how much swap you need to run your > applications. The amount of swap space should be more related to how much > stuff you want to have in memory at one time, I would think. I wish I knew the exact history behind it myself :-), but in my experience it's been a good "yardstick", at least for starters. Obviously, you don't have to adhere to it (I could probably get by with 50mb on my 32MB RAM workstation since I'm running X and not using swap), but again it's a starting point. > The size of the recommendation should change depending on whether or not > the swap area is the total virtual address space or just an extension of > the RAM (i.e. > > sizeof(virtual addr space) == sizeof(RAM)+ sizeof(swap) > > instead of just > > sizeof(virtual addr space) == sizeof(swap) FreeBSD uses method #1. It's all the same to the VM system. > ). If on a system doing the latter, 20Mb is definitely not enough swap for > 16Mb of RAM. I don't really know which category FreeBSD falls into (it > could be that any recent OS uses the former method...I don't know). I don't know of any OSs that consider the swap to be total memory available. The three that I know of that use swap other than UNIXen are OS/2, Windows95 and Windows, and they use method #1 too. Doug White | University of Oregon Internet: dwhite@resnet.uoregon.edu | Residence Networking Assistant http://gladstone.uoregon.edu/~dwhite | Computer Science Major