multiple lvm2-snapshots on the same origin -> device-mapper error
Hi!
I'm running in trouble creating more than 16 snapshots of the same origin:
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# /sbin/lvcreate -s -L150M -n rootfs_node17 /dev/vg/ro_rootfs File descriptor 5 left open File descriptor 6 left open Rounding up size to full physical extent 152.00 MB device-mapper ioctl cmd 9 failed: Cannot allocate memory Couldn't load device 'vg-rootfs_node8'. Problem reactivating origin ro_rootfs
# lvm version LVM version: 2.01.04 (2005-02-09) Library version: 1.01.00-ioctl (2005-01-17) Driver version: 4.4.0
# uname -a Linux hostname 2.6.11.12-xen0 #1 Thu Aug 4 00:45:12 BST 2005 i686 GNU/Linux
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Browsing the mailing list archives I didn't find a suitable solution although the problem was mentioned before, e.g. on
http://lists.xensource.com/archives/html/xen-devel/2004-09/msg00426.html
Any ideas?
Thank you in advance.
Patrick Reinhardt
Quoted 2 lines · Patrick Reinhardt
Hi!
I'm running in trouble creating more than 16 snapshots of the same origin:
We don't have a solution for that particular problem yet, but we do have code changes that should avoid the risk of the system locking up when it happens.
This needs the latest development packages for LVM2 (2.02.*) and device-mapper (1.02.*).
And a kernel containing the patches:
dm-rename-frozen_bdev.patch
dm-skip-lockfs.patch
dm-ioctl-skip-lockfs.patch
dm-snapshot-metadata-reading-separation.patch
dm-snapshot-load-metadata-on-creation.patch
dm-ioctl-reduce-pf-memalloc-usage.patch
from http://www.kernel.org/pub/linux/kernel/people/agk/patches/2.6/editing/
There are still some snapshot problems that have shown up while testing the RHEL4 kernel (with all the above patches applied) that we haven't got to the bottom of yet:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=174636
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=174742
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=174753
Alasdair
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Hi!
Thank you for the hints.
Quoted 2 lines · Alasdair G Kergon
We don't have a solution for that particular problem yet, but we do have code changes that should avoid the risk of the system locking up when it happens.
In fact i need about 40 snapshots of a single filesystem for xen. Do you have any idea how to circumvent the problem? Maybe by creating 3 identical origin filesystems and distribute the snapshots?
Thank you in advance.
Patrick Reinhardt
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Hi!
Thank you for the hints.
Quoted 1 line · Alasdair G Kergon
We don't have a solution for that particular problem yet, but we do
have code
Quoted 1 line
changes that should avoid the risk of the system locking up when it
happens.
In fact I need about 40 snapshots of a single filesystem for xen. Do you have any idea how to circumvent the problem? Maybe by creating 3 identical origin filesystems and distribute the snapshots?
Thank you in advance.
Patrick Reinhardt
Quoted 10 lines · Patrick Reinhardt
Hi!
Thank you for the hints.Quoted 1 line · Alasdair G Kergon
We don't have a solution for that particular problem yet, but we do
have code
Quoted 8 lines
Quoted 1 line
changes that should avoid the risk of the system locking up when it
happens.
In fact I need about 40 snapshots of a single filesystem for xen. Do you have any idea how to circumvent the problem? Maybe by creating 3 identical origin filesystems and distribute the snapshots?
Looks to me like you really want a kind of cluster filesystem ...
Ciao
Klaus
Signature · 8 lines
Mit freundlichen Gr�ssen / best regards Klaus Strebel, Dipl.-Inform. (FH), mailto:[email protected] /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \