From mboxrd@z Thu Jan 1 00:00:00 1970 From: Craig Boston Subject: Re: Efficient way to import snapshots? Date: Tue, 31 Jul 2007 08:53:32 -0500 Message-ID: <20070731135332.GA58867@nowhere> References: <20070730180710.GA64467@nowhere> <20070730192922.GB64467@nowhere> <20070730222028.GE64467@nowhere> <20070731011707.GA91930@nowhere> <20070731042347.GG25876@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , Junio C Hamano , Git Mailing List To: Theodore Tso X-From: git-owner@vger.kernel.org Tue Jul 31 15:53:41 2007 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1IFsAO-00009u-Ph for gcvg-git@gmane.org; Tue, 31 Jul 2007 15:53:41 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755758AbXGaNxh (ORCPT ); Tue, 31 Jul 2007 09:53:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755343AbXGaNxh (ORCPT ); Tue, 31 Jul 2007 09:53:37 -0400 Received: from ion.gank.org ([69.55.238.164]:1135 "EHLO ion.gank.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755739AbXGaNxf (ORCPT ); Tue, 31 Jul 2007 09:53:35 -0400 Received: by ion.gank.org (Postfix, from userid 1001) id 472FC11246; Tue, 31 Jul 2007 08:53:33 -0500 (CDT) Content-Disposition: inline In-Reply-To: <20070731042347.GG25876@thunk.org> User-Agent: Mutt/1.4.2.2i Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Tue, Jul 31, 2007 at 12:23:47AM -0400, Theodore Tso wrote: > On Mon, Jul 30, 2007 at 06:44:13PM -0700, Linus Torvalds wrote: > > > > Oh, ok. Solaris. For reference, as I mentioned to Linus & Junio in an excessively verbose, and probably uninteresting to most of the git-list members, message about the performance characteristics of ZFS, I'm actually running FreeBSD-current with the experimental port of ZFS. So, even less tested & tuned than it is on Solaris. Part of what I'm doing is stress testing the filesystem on machines with less than the recommended memory. Even if performance is suboptimal, it should at least not break anything. > Craig, it might be interesting to see what sort of results you get if > you use UFS instead of ZFS in your low-memory constrained > environment... I just so happen to be rebuilding the zfs pool on that server this morning in order to add more swap, so your wish(1tcl) is my rcmd(3). Same machine, on a UFS filesystem (single disk, since zfs was doing the RAID), with the cache tuning parameters reset back to defaults: First 'git status' after a reboot: git status 2.23s user 2.23s system 17% cpu 24.987 total Second: git status 1.81s user 1.34s system 98% cpu 3.188 total Third: git status 1.76s user 1.45s system 98% cpu 3.252 total So I definitely think the problem is just that with its increased overhead, ZFS simply can't keep all the metadata in the cache with the available memory. Craig