[linux-lvm] LVM Snapshot create trouble
TDC at yesinc.com
Mon Mar 6 19:21:36 UTC 2006
This post relates to an issue posted by Steffen Plotner back in
I am experiencing the same type of problem.
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
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
Can anyone reproduce this problem? Now there are at least two of us
with the same exact issue.
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