From owner-freebsd-hackers Thu Aug 17 18:56:54 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.129.65]) by hub.freebsd.org (Postfix) with ESMTP id 97F9637BB82 for ; Thu, 17 Aug 2000 18:51:48 -0700 (PDT) Received: from chmls05.mediaone.net (chmls05.mediaone.net [24.147.1.143]) by mx1.FreeBSD.org (Postfix) with ESMTP id E4A156E3B8D for ; Thu, 17 Aug 2000 14:34:21 -0700 (PDT) Received: from ahp3 (ahp.ne.mediaone.net [24.128.184.250]) by chmls05.mediaone.net (8.8.7/8.8.7) with SMTP id RAA14092; Thu, 17 Aug 2000 17:34:12 -0400 (EDT) From: "Allen Pulsifer" To: "Matt Dillon" Cc: Subject: RE: what to do about /tmp Date: Thu, 17 Aug 2000 17:34:12 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2911.0) In-Reply-To: <200008151705.KAA29836@earth.backplane.com> Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Matt, I noticed /tmp and /var/tmp are used slightly differently, for example, the contents of /tmp are not expected to survive a reboot, while /var/tmp is used for files you might need after a crash, like vi recovery files. It makes sense to me to mount /tmp using MFS. The symantics of /tmp and VM are very close: its a bunch of data that you would like to keep in RAM if possible, but can be pushed out to disk if needed. And you don't care about metadata, file system consistency and whether it survives a crash. One advantage of mounting /tmp with MFS is that you don't have use up another disk partition. Performance-wise, I would think data moves something like this: /tmp on MFS: application data --> kernel VM --> paged to disk /tmp on FFS: application data --> kernel file buffer --> flushed to disk Is that basically correct? What makes MFS less efficient than FFS? What would be the implications of creating a 512 MB swap partition and mounting an MFS /tmp? Thanks, Allen To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message