From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: Efficient way to import snapshots? Date: Tue, 31 Jul 2007 08:50:19 -0700 (PDT) Message-ID: References: <20070730180710.GA64467@nowhere> <20070730192922.GB64467@nowhere> <20070730222028.GE64467@nowhere> <20070731011707.GA91930@nowhere> <20070731042347.GG25876@thunk.org> <20070731135332.GA58867@nowhere> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Cc: Theodore Tso , Junio C Hamano , Git Mailing List To: Craig Boston X-From: git-owner@vger.kernel.org Tue Jul 31 17:50:46 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 1IFtzd-0002ho-O1 for gcvg-git@gmane.org; Tue, 31 Jul 2007 17:50:42 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759954AbXGaPug (ORCPT ); Tue, 31 Jul 2007 11:50:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759018AbXGaPuf (ORCPT ); Tue, 31 Jul 2007 11:50:35 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:45411 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756625AbXGaPue (ORCPT ); Tue, 31 Jul 2007 11:50:34 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [207.189.120.55]) by smtp2.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id l6VFoQHN020600 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 31 Jul 2007 08:50:27 -0700 Received: from localhost (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id l6VFoJ4Q009379; Tue, 31 Jul 2007 08:50:21 -0700 In-Reply-To: <20070731135332.GA58867@nowhere> X-Spam-Status: No, hits=-2.688 required=5 tests=AWL,BAYES_00,TW_ZF X-Spam-Checker-Version: SpamAssassin 3.1.0-osdl_revision__1.16__ X-MIMEDefang-Filter: osdl$Revision: 1.181 $ X-Scanned-By: MIMEDefang 2.53 on 207.189.120.14 Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Tue, 31 Jul 2007, Craig Boston wrote: > > 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). You, sir, are a total geek. I'm not sure if that's a compliment or a curse. > 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. Very interesting. And thanks. The whole "ZFS is great" internet meme seems to be partly due to not a lot of people having used or compared it in real life. I'm sure it's wonderful for some things, but it clearly does have a lot of downsides too. Linus