[linux-lvm] LVM2 Error when creating snapshot

[linux-lvm] LVM2 Error when creating snapshot

[Kelly Sauke]

I get this error whenever I create a bunch of snapshots.  I have 36 filesystems
in my vg.  If I walk through them creating a snapshot on each one, the last 4
fail.  They fail with the below error.  I did the order backwards and got the
same results so its not dependant on the lv I'm snapshotting, it appears to be
dependant upon the number of snapshots I'm creating.


/usr/sbin/lvcreate -L 1G -p r -s -n save_perpet2-20060619161740
/dev/svg/save_perpet2lv
  device-mapper: reload ioctl failed: Cannot allocate memory
  Failed to suspend origin save_perpet2lv



It creates the snapshot devices in /dev/mapper.

ls -l /dev/mapper/svg-save_perpet2--20060619161740*
brw-rw----  1 root disk 253, 159 Jun 20 15:19
/dev/mapper/svg-save_perpet2--20060619161740
brw-rw----  1 root disk 253, 158 Jun 20 15:19
/dev/mapper/svg-save_perpet2--20060619161740-cow

but it doesn't create any devices in /dev/svg.


It also is available to query with lvdisplay.

lvdisplay /dev/svg/save_perpet2-20060619161740
  --- Logical volume ---
  LV Name                /dev/svg/save_perpet2-20060619161740
  VG Name                svg
  LV UUID                oP2nDj-aa7p-dS3Q-4VdH-gk8r-x5C8-Akg78K
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                1.00 GB
  Current LE             256
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           253:159

I can't do anything with that volume other than remove it though.



I'm running RHEL 4 U 3 with the beta hugemem kernel installed.  I installed the
beta kernel as the request of redhat support.

device-mapper-1.02.02-3.0.RHEL4
udev-039-10.12.EL4
kernel-hugemem-2.6.9-39.EL

Any insight would be appreciated.

Re: [linux-lvm] LVM2 Error when creating snapshot

[Brian J. Murrell]

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On Tue, 2006-06-20 at 15:30 -0500, Kelly Sauke wrote:
> 
> 
> I get this error whenever I create a bunch of snapshots.  I have 36 filesystems
> in my vg.  If I walk through them creating a snapshot on each one, the last 4
> fail.  They fail with the below error.  I did the order backwards and got the
> same results so its not dependant on the lv I'm snapshotting, it appears to be
> dependant upon the number of snapshots I'm creating.
> 
> 
> /usr/sbin/lvcreate -L 1G -p r -s -n save_perpet2-20060619161740
> /dev/svg/save_perpet2lv
>   device-mapper: reload ioctl failed: Cannot allocate memory

Sadly, you are getting about as much response as I got to both a posting
here and a bug filed with redhat about this issue.

This appears to be a "mis-use" of a particular kernel memory allocation
function that is used to reallocate a pool until it reaches the maximum
size that that particular function is capable of allocating.  I don't
recall the details at the moment however.  The bug in redhat's bugzilla
has a pretty good accounting IIRC.

b.

-- 
My other computer is your Microsoft Windows server.

Brian J. Murrell

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