From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id iA15kCr27079 for ; Mon, 1 Nov 2004 00:46:12 -0500 Received: from geeksite.geeksite.org (ibz.geeksite.org [63.227.242.54]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id iA15kA9Z002889 for ; Mon, 1 Nov 2004 00:46:11 -0500 Received: from localhost (unknown [127.0.0.1]) by geeksite.geeksite.org (Postfix) with ESMTP id 515FA2E7173 for ; Sun, 31 Oct 2004 22:54:37 -0700 (MST) Received: from geeksite.geeksite.org ([127.0.0.1]) by localhost (geeksite [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 24185-10 for ; Sun, 31 Oct 2004 22:54:33 -0700 (MST) Received: from [192.168.0.7] (xscott.theserrs.net [63.227.243.149]) by geeksite.geeksite.org (Postfix) with ESMTP id 97EF92F564B for ; Sun, 31 Oct 2004 22:54:33 -0700 (MST) Message-ID: <4185DBA8.7060605@theserrs.net> Date: Sun, 31 Oct 2004 23:46:00 -0700 From: Scott Serr MIME-Version: 1.0 Subject: Re: [linux-lvm] Software raid on top of lvm logical volume References: <41801ADE.6030308@monjoin.net> <20041028011738.GD13737@kluge.net> <41814060.4040400@mikebabcock.ca> <41851771.4060203@markus.org> In-Reply-To: <41851771.4060203@markus.org> Content-Transfer-Encoding: 7bit Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: LVM general discussion and development I've done something like Markus explained. I had this email ready to go a couple days ago, but the compose window was hidden for a while... I hope it's not too stale for the original poster of this thread: 2.4.26 with latest LVM2 works well. I did something crazy, alot of people probably don't understand why. I have software RAID5. md0 = hda5 hdb5 hdc5 hdd5 hde5 md1 = hda6 hdb6 hdc6 hdd6 hde6 md2 = hda7 hdb7 hdc7 hdd7 md3 = hda8 hdb8 hdc8 hdd8 Then I have just one big vgdata and one lvdata. Why would I want to do this? I couldn't find any other way to have redundancy and be flexible. If I replace a physical disk with a larger one, for instance hde needs to be bigger so I can make md2 and md3 stretch across that disk too... then I am able to do pvmove from md2 to a scratch disk, recreate md2 across hda7-hde7, then pvmove back. -Scott Markus Baertschi wrote: > Michael T. Babcock wrote: > >> >> I've thought about this numerous times -- there is the distinct >> resizing advantage. Namely, if I create a software RAID partition, I >> can't resize it afterward without destroying it. I have for example, >> on occasion, had three disks set up where 1/3 of each was devoted to >> a RAID-0 very fast striping set for data transfers that had to be >> fast but if they were lost it wasn't critical, and 2/3 was set up as >> RAID-5 for reliability of another set of data. >> >> I understand this may not be optimal in some situations, but some of >> us don't have thousands of dollars for SCSI HW RAID controllers. > > > You can make life easier by creating several raid arrays on the same > disks and tie them together with LVM. > For example split your three 160GB drives into 4 partitions each and > create a raid over the three disks. > > sda -> sda1+sda2+sda3+sda4, etc. > md0 = sda1+sdb1+sdc1, md1=sda2+sdb2+sdc2, etc. > > Markus >