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 k26JLs112896 for ; Mon, 6 Mar 2006 14:21:54 -0500 Received: from mailgate1.yesinc.com (mailgate1.yesinc.com [216.204.185.106]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id k26JLr97019489 for ; Mon, 6 Mar 2006 14:21:53 -0500 Received: from mailgate1.yesinc.com (localhost.localdomain [127.0.0.1]) by mailgate1.yesinc.com (Postfix) with ESMTP id 205B4D7630 for ; Mon, 6 Mar 2006 14:21:48 -0500 (EST) Received: from fs02.yesinc.com (fs02.yesinc.com [172.16.0.2]) by mailgate1.yesinc.com (Postfix) with ESMTP id DB824D762D for ; Mon, 6 Mar 2006 14:21:42 -0500 (EST) Message-Id: Date: Mon, 06 Mar 2006 14:21:36 -0500 From: "Tim Cary" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline Subject: [linux-lvm] LVM Snapshot create trouble 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" To: linux-lvm@redhat.com Hello, This post relates to an issue posted by Steffen Plotner back in December. See https://www.redhat.com/archives/linux-lvm/2005-December/msg00105.html I am experiencing the same type of problem. On 2.6.13-1.1532_FC4: When a lot of write activity is going on my server goes into a dead lock trying to create a snapshot. The write activity is from creating the snap itself, as disk i/o normally is not intense on this server. lvm_snap_copy> source: /dev/vg_scsi_0/lv_os_root lvm_snap_copy> target: /dev/vg_scsi_0/lv_os_root_alt lvm_snap_create> source: /dev/vg_scsi_0/lv_os_root lvm_snap_create> target: snap lvm_snap_create> snap_space: 15% lvm_snap_create> source uuid: Jm4sGV-fGt5-XRHl-ESds-AERY-pZtq-GOg8Tu lvm_snap_create> short name: lv_os_root lvm_snap_create> size: 8388608000 bytes lvm_snap_create> snap_size: 1200 Mb lvm_snap_create> lvcreate -s -L1200 -n lv_os_root_snap /dev/vg_scsi_0/lv_os_root Rounding up size to full physical extent 1.19 GB At this point no I/O was possible. No ssh, no x terminal, no logging into the console, nothing at all! Disk activity was null. In VNC you could see the load window all black filled. I had to push the reset button on the server. This is on some very decent hardware- 3Ghz Xenon, 4Gb RAM, 7200RPM SCSI Hardware raid controller drives. When I run the same command on a different system, same hardware (but a bit less loaded CPU wise), I did not yet have this problem, however I have been able to reproduce this same type of issue, it seems when there is continuous i/o, one can not remove the snapshot until all i/o ceases. Can anyone reproduce this problem? Now there are at least two of us with the same exact issue. Tim