From owner-freebsd-fs@FreeBSD.ORG Mon Jun 22 13:21:48 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 49008106568A for ; Mon, 22 Jun 2009 13:21:48 +0000 (UTC) (envelope-from dan.naumov@gmail.com) Received: from mail-yx0-f200.google.com (mail-yx0-f200.google.com [209.85.210.200]) by mx1.freebsd.org (Postfix) with ESMTP id 0014C8FC16 for ; Mon, 22 Jun 2009 13:21:47 +0000 (UTC) (envelope-from dan.naumov@gmail.com) Received: by yxe38 with SMTP id 38so1977412yxe.3 for ; Mon, 22 Jun 2009 06:21:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=MLgQQIAo+Yum2NYQ6gzSGqOzor/30A0UOTqKrLcJd28=; b=qzEsnXwxUeLQSu/90FJH9x+a0O3Y0rAjeUnJHKmbZk6sPCbxMdwBGBTSxb/vM2przb 2haKTJIA1LGgTr5F30tV72hD9ysVxSTE4B2I4im+8xbQu4YRvMpBcY9KVvKaiiAh0+LS Jj/ToTitXIK9RSCcpONnyLrCUh/l3nYj+42f4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=p26kHWUKTl4Rq3nLs4+3ybMDvq1PKoAcvTkuoG/OXevFNRRxksK0NCR6CmuypCgcI4 2Z1QyRK8bAxZQ2EjNYP284p7kJceZIYybRXaQC1CBoIEycPzm7mS/PYbxCnNsrPMcSgn eFLWLFlPP8mVyrAVU72jxV7pkU/7xXOSgPvcY= MIME-Version: 1.0 Received: by 10.100.141.15 with SMTP id o15mr8141531and.20.1245676508090; Mon, 22 Jun 2009 06:15:08 -0700 (PDT) In-Reply-To: <289445.67836.qm@web37308.mail.mud.yahoo.com> References: <570433.20373.qm@web37308.mail.mud.yahoo.com> <289445.67836.qm@web37308.mail.mud.yahoo.com> Date: Mon, 22 Jun 2009 16:15:08 +0300 Message-ID: From: Dan Naumov To: Simun Mikecin Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: ufs2 / softupdates / ZFS / disk write cache X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Jun 2009 13:21:48 -0000 On Mon, Jun 22, 2009 at 3:19 PM, Simun Mikecin wrote: > 2) I wouldn't use UFS+SU on [S]ATA disks because your background fsck will > simetimes give up stating something like "unexpected softupdates > inconsistency" (unless you had disabled write cache, which you don't really > want to) and you will have to do a manual foreground fsck yourself. > The choice should (in my opinion) be: ZFS for amd64, UFS+gjournal for i386. > Both (ZFS and UFS+gjournal) will not have any recovery penalty if you have > write cache enabled. You seem to be thinking the way I am thinking :) My biggest concern is for the new users coming to FreeBSD, most of whom are going to end up with having UFS2+SU on their SATA disks, which is not the best defaults to have. I wonder if people running away screaming from sysinstall code has anything to do with why gjournal and zfs are not suggested as an option during the system installation procedure. Is the general consensus that adding these options to the install will only happen if/when FreeBSD moves on to a new installer system? Out of curiosity, how many beers would folks have to chime in for somebody knowledgeable enough to implement direct support for gjournal and zfs into sysinstall? :) > If you have a controller with battery backup cache, you could even run ZFS > with disabled cache flush (i don't know wheter it can be disabled on > gjournal), but I'm not sure that you will get any real word performance > improvement by doing it. In their own documentation, SUN recommends against disabling cache flushing in most cases, as the performance gain is going to be very negligible. However, there is a special case with "smart" SAN devices, where SUN strongly recommends disabling cache flushes because otherwise you are going to suffer through serious performance losses. - Sincerely, Dan Naumov