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 (8.11.6/8.11.6) with ESMTP id j239nhK27492 for ; Thu, 3 Mar 2005 04:49:43 -0500 Received: from w3f.coventive.coms.coventive.com (202-145-53-92.adsl.ttn.net [202.145.53.92]) by mx3.redhat.com (8.12.11/8.12.11) with ESMTP id j239nSWm028449 for ; Thu, 3 Mar 2005 04:49:29 -0500 Received: from [192.168.20.46] (pc46.sa.coventive.com [192.168.20.46]) by w3f.coventive.coms.coventive.com (8.11.6/8.11.6) with ESMTP id j239nMB32668 for ; Thu, 3 Mar 2005 17:49:24 +0800 Message-ID: <4226DDFB.8000801@coventive.com> Date: Thu, 03 Mar 2005 17:50:51 +0800 From: Chung Hsien Hu MIME-Version: 1.0 References: In-Reply-To: Content-Transfer-Encoding: 7bit Subject: [linux-lvm] snapshot problem when memory size is over 4GB 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 Hi, I got a server with Tyan5350 mainboard and 8GB ECC RAM. And it seem that snapshot didn't work in either LVM1 or LVM2 when the memory over 4GB is plugged. We have HIGHMEM64G=y kernel option been set. Everything is ok when the comination is "snapshot + 4GB RAM" or "no snapshot + 8GB RAM"... Any clues? PS: Hope you could understand my question, english is not my mother language. :( 1. in linux-2.4.27 + LVM-1.0.8, it failed to activate the VG with any existed snapshot volume. bash-2.03# vgchange -ay vgchange -- ERROR "Bad address" activating volume group "storage" 2. And again, in linux-2.4.27 + LVM-1.0.8, it failed to create snapshot volume. bash-2.03# lvcreate -A n -s -n test_snap -l 16 /dev/storage/test lvcreate -- WARNING: the snapshot will be automatically disabled once it gets full lvcreate -- INFO: using default snapshot chunk size of 64 KB for "/dev/storage/test_snap" lvcreate -- ERROR "Cannot allocate memory" creating VGDA for "/dev/storage/test_snap" in kernel 3. Then I turn to test linux-2.6.10 + LVM2. This time I can create a snapshot and it work well until I reboot the system. The system will crash when I try to make a tarfile over the original volume. bash-2.03# lvm version LVM version: 2.00.31 (2004-12-12) Library version: 1.00.19-ioctl (2004-07-03) Driver version: 4.3.0 bash-2.03# lvm lvscan ACTIVE Original '/dev/storage/test' [1.95 GB] inherit ACTIVE '/dev/storage/xfs' [1.95 GB] inherit ACTIVE Snapshot '/dev/storage/test_snap' [500.00 MB] inherit ACTIVE '/dev/storage/sysvolume' [2.44 GB] inherit bash-2.03# tar cvf /mnt/xfs/test.tar /mnt/test a /mnt/test/ directory a /mnt/test/ACARD101RC3.iso 67534848 bytes, 131904 tape blocks ===>SYSTEM CRASHED!!...... system halt and the last line of messages on screen is: <0>Kernel panic - not syncing: Fatal execption in interrupt It's interesting to mention that the snapshot work well before reboot. Seem it is kind of problem relate to VFS cache, snapshot and HIGHMEM support? -- Mozo Hu. mozo@coventive R&D Assistant Manager, Coventive Advance Technologies