From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx3.redhat.com (mx3.redhat.com [172.16.48.32]) by int-mx1.corp.redhat.com (8.12.11.20060308/8.12.11) with ESMTP id k3U7U8Xp002709 for ; Sun, 30 Apr 2006 03:30:08 -0400 Received: from ns1.ballihost.com (ns1.ballihost.com [69.57.158.65]) by mx3.redhat.com (8.13.1/8.13.1) with SMTP id k3U7U0MW015007 for ; Sun, 30 Apr 2006 03:30:01 -0400 Message-ID: <1282.85.107.14.146.1146382053.squirrel@85.107.14.146> Date: Sun, 30 Apr 2006 10:27:33 +0300 (EEST) From: "Omer Faruk Sen" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [linux-lvm] realtime snapshot or ? Reply-To: omer@faruk.net, 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" To: linux-lvm@redhat.com Hi, I am looking for a solution that I can use as a realtime snapshot or maybe it should be called realtime raid or whatever. What I want is like this: Say I have a VG1 and VG2. I use VG2 as a backup VG2 and some machines will mount it as read-only( I mean LV2 on VG2) My main server (which runs mysql and all write operations will go to LV1) will run mysql and use /sql as its --data-dir. /sql uses /dev/VG1/LV1. But every write operations on LV1 that resides on VG1 should go to VG2 thus to LV2 too. I have found that nbd ord drbd does similar things. But nbd just exports a block device (JUST ONE block device) so other machines can mount it. DRBD is closer to what I want but I can't mount drbd on secondary (backup machine) even as read-only To depict what I want rw |SERVER1| ----> MYSQL DATA ----> | REMOTE STORAGE | VG1/LV1 | |---> | REMOTE STORAGE | VG2/LV2 --| rw | | | ro | /backupsql/--- |SERVER2| <--| -- Omer Faruk Sen http://www.faruk.net