From owner-freebsd-current@FreeBSD.ORG Thu Nov 15 15:14:33 2007 Return-Path: Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 72D3716A468 for ; Thu, 15 Nov 2007 15:14:33 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (lurza.secnetix.de [IPv6:2001:1b20:1:3::1]) by mx1.freebsd.org (Postfix) with ESMTP id DF17313C468 for ; Thu, 15 Nov 2007 15:14:32 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (localhost [127.0.0.1]) by lurza.secnetix.de (8.14.1/8.14.1) with ESMTP id lAFFEGwW072977; Thu, 15 Nov 2007 16:14:22 +0100 (CET) (envelope-from oliver.fromme@secnetix.de) Received: (from olli@localhost) by lurza.secnetix.de (8.14.1/8.14.1/Submit) id lAFFEFFs072976; Thu, 15 Nov 2007 16:14:15 +0100 (CET) (envelope-from olli) Date: Thu, 15 Nov 2007 16:14:15 +0100 (CET) Message-Id: <200711151514.lAFFEFFs072976@lurza.secnetix.de> From: Oliver Fromme To: freebsd-current@FreeBSD.ORG, arne_woerner@yahoo.com, bsd@fluffles.net In-Reply-To: <165798.11850.qm@web30314.mail.mud.yahoo.com> X-Newsgroups: list.freebsd-current User-Agent: tin/1.8.3-20070201 ("Scotasay") (UNIX) (FreeBSD/6.2-STABLE-20070808 (i386)) MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.2 (lurza.secnetix.de [127.0.0.1]); Thu, 15 Nov 2007 16:14:22 +0100 (CET) Cc: Subject: Re: geom_raid5 inclusion in HEAD? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-current@FreeBSD.ORG, arne_woerner@yahoo.com, bsd@fluffles.net List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Nov 2007 15:14:33 -0000 Arne Wörner wrote: > Oliver Fromme wrote: > > Just a small question: I noticed that the new gvinum > > raid5 implementation (in P4) allows adding disks to an > > existing RAID5, even while it is running. Does geom_raid5 > > support that, too? (ZFS doesn't, unfortunately.) > > Nope... graid5 doesnt do such things... I found no way, that could do it > without hurting the disks too much (I was afraid, that a power failure could > destroy the necessary knowledge about the size of the new-config-area; and I > didnt know how to do the beginning: it seemed like the first few blocks need a > special treatment, because there the new-config-area and the old-config-area > overlap)... OK. I don't know the inner workings of geom_raid5, so I can't tell how difficult it would be to implement there. Here's a little description and some ASCII graphics that explin how growing RAID5 was implemented in the new gvinum: http://lists.freebsd.org/pipermail/p4-projects/2007-July/020082.html > But Veronica is developing a tool, that can do it in offline mode... With > service interruption... > > But growfs induces a service interruption anyway and it is buggy, if u do > not zero the new area... Veronica filed a bug report about this... Hm. I used growfs only once, and it worked fine. Was there a regression introduced at some point? It should certainly be fixed, because growfs seem to be very useful. About service interruption: growfs only takes a few seconds, which might be acceptable in most cases. But taking a whole RAID5 down to add disks and then rebuilding it takes a _lot_ longer. Therefore I think the feature to add disks to a live RAID5 would be very valuable. > Nowadays it is common practice to have 2 ot more hosts, that can substitute > each other (hot-standby or how they call it today), so that it doesnt matter, > if a box is damaged or in maintenance mode or... isnt it? It depends. Building a fail-over cluster with FreeBSD is not trivial if you need a synchronized, consistent and reliable file system on all of the nodes. Of course you can use third-party black boxes such as a cluster of NetApp Filers or whatever. That would work (I've put such setups into production myself), but it costs a non-negligible amount of money, and it's certainly not suitable for everyone. YMMV, of course. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them.