From owner-freebsd-questions@FreeBSD.ORG Wed Jan 14 16:04:43 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 092AA10658CB for ; Wed, 14 Jan 2009 16:04:42 +0000 (UTC) (envelope-from psteele@maxiscale.com) Received: from arcturus.maxiscale.com (arcturus.maxiscale.com [76.231.178.136]) by mx1.freebsd.org (Postfix) with ESMTP id BAA618FC16 for ; Wed, 14 Jan 2009 16:04:42 +0000 (UTC) (envelope-from psteele@maxiscale.com) X-ASG-Debug-ID: 1231949058-205700010000-jLrpzn X-Barracuda-URL: http://10.100.1.25:8000/cgi-bin/mark.cgi Received: from polaris.maxiscale.com (localhost [127.0.0.1]) by arcturus.maxiscale.com (Spam Firewall) with ESMTP id 2D35E369D3 for ; Wed, 14 Jan 2009 08:04:18 -0800 (PST) Received: from polaris.maxiscale.com (polaris.maxiscale.com [10.100.1.24]) by arcturus.maxiscale.com with ESMTP id 93JONZKZ2Poygfof for ; Wed, 14 Jan 2009 08:04:18 -0800 (PST) X-ASG-Whitelist: Client X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 X-ASG-Orig-Subj: Should swap space be mirrored via geom? Date: Wed, 14 Jan 2009 08:04:17 -0800 Message-ID: <2ACA3DE8F9758A48B8BE2C7A847F91F247A1E1@polaris.maxiscale.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Should swap space be mirrored via geom? Thread-Index: Acl2YcB+wSSje52EQz2d5vSxVGDSQQ== From: "Peter Steele" To: X-Barracuda-Connect: polaris.maxiscale.com[10.100.1.24] X-Barracuda-Start-Time: 1231949059 X-Barracuda-Virus-Scanned: by Barracuda Spam Firewall at maxiscale.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Should swap space be mirrored via geom? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Jan 2009 16:04:44 -0000 We have systems setup using geom based mirroring where the drives are partitioned into three slices, one for the OS, one for the swap partition, and one for our application data. We have four hot-swappable SATA drives per system. At present we only have the OS slice mirrored with geom, and our own data partition is definitely not a candidate for mirroring. The swap slice is not mirrored, so we end up with 4x4GB of space on each system (which is probably way more than we need). =20 We have been debating whether or we should mirror the swap partitions as well. I set it up not mirrored based on some articles I read on the net, but we're concerned what might happen to a system if a drive died at a time when the its swap partition contained active pages. My first reaction would be that the applications bound to these pages would crash, something that would not happen if we used swap mirroring. =20 Can anyone shed some light on this? =20