From owner-freebsd-arch Sat Dec 8 20:15:21 2001 Delivered-To: freebsd-arch@freebsd.org Received: from ambrisko.com (adsl-64-174-51-42.dsl.snfc21.pacbell.net [64.174.51.42]) by hub.freebsd.org (Postfix) with ESMTP id A77ED37B416 for ; Sat, 8 Dec 2001 20:15:17 -0800 (PST) Received: (from ambrisko@localhost) by ambrisko.com (8.11.6/8.11.6) id fB94Eoa19371; Sat, 8 Dec 2001 20:14:51 -0800 (PST) (envelope-from ambrisko) From: Doug Ambrisko Message-Id: <200112090414.fB94Eoa19371@ambrisko.com> Subject: Re: Using a larger block size on large filesystems In-Reply-To: <200112081909.fB8J9TB06131@apollo.backplane.com> To: Matthew Dillon Date: Sat, 8 Dec 2001 20:14:50 -0800 (PST) Cc: freebsd-arch@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL94b (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matthew Dillon writes: | :I know you've mentioned this before. Are there technical reasons behind | :this? I believe you mentioned something about the buffer cache? Would | :you be willing to add it as an option since so many others seem to want | :it? | | Most of the stuff that winds up in /tmp is garbage. There is no good | reason to burden our VM system with unnecessary garbage and I know of | no performance issues involved with people using /tmp files that requires | MFS or MD. It's an unnecessary waste of memory and an unnecessary burden | on our VM system. Unless you want a cvs pserver to run fast! I did some benchmarks a while back (port 4.2 I think) in which I had /tmp on soft-updates. It was a little faster on "cvs co freebsd" for example. CVS pserver was running on a dedicated machine and the CVS client was on another. Switched to MFS made a significant improvement. I don't have the number anymore (changed employers). I think the issue here is that CVS on the pserver checks out a sparse tree of the meta data for the each directory that you need. I recall directory operations are sync'd. So creating all the directories and syncing them becomes the gating factor. BTW we ended up sticking a lot of memory in that machine to prevent swaping. We had about 20 people using it. One thing I didn't try was mounting /tmp as async and maybe noatime. That might be an interesting thing to try. Doug A. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message