snapshot backup of 25GB container | OpenVZ, Proxmox

There is 2 containers:

1st - 400Mb
2nd - ~25Gb

1st container(400Mb) works fine in both of backup modes (SUSPEND and SNAPSHOT). But 2nd container(25Gb) make backup only in SUSPEND mode. SNAPSHOT mode is always failed.

Both of containers make backups in the same folder (/backups). Here is pve storage config /etc/pve/storage.cfg:

dir: local
    path /var/lib/vz
    content images,iso,vztmpl,rootdir
    maxfiles 0

dir: backups
    path /backups
    shared
    content backup
    maxfiles 3

And /etc/pve/vzdump.cron config:

PATH="/usr/sbin:/usr/bin:/sbin:/bin"

0 4 * * 3,7         root vzdump 100 --quiet 1 --mode snapshot --node proxmox --compress lzo --storage backups
15 4 * * 3,7         root vzdump 101 --quiet 1 --mode snapshot --node proxmox --compress lzo --storage backups

Here is my storage configuratin: pvdisplay:

  --- Physical volume ---
  PV Name               /dev/md1
  VG Name               pve1
  PV Size               930.89 GiB / not usable 4.81 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              238306
  Free PE               14060
  Allocated PE          224246
  PV UUID               7bVuGz-Bgty-Tq9f-....

And lvdisplay:

  --- Logical volume ---
  LV Path                /dev/pve1/swap
  LV Name                swap
  VG Name                pve1
  LV UUID                QFrmt8-FgAl-4Iz1-....
  LV Write Access        read/write
  LV Creation host, time proxmox, 2013-07-23 15:53:26 +0400
  LV Status              available
  # open                 1
  LV Size                7.00 GiB
  Current LE             1792
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/pve1/root
  LV Name                root
  VG Name                pve1
  LV UUID                LZZ4EX-QDyr-AcG9-....
  LV Write Access        read/write
  LV Creation host, time proxmox, 2013-07-23 15:53:34 +0400
  LV Status              available
  # open                 1
  LV Size                96.00 GiB
  Current LE             24576
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

  --- Logical volume ---
  LV Path                /dev/pve1/data
  LV Name                data
  VG Name                pve1
  LV UUID                x1i9Wo-tdDW-RcLL-....
  LV Write Access        read/write
  LV Creation host, time proxmox, 2013-07-23 15:53:51 +0400
  LV Status              available
  # open                 1
  LV Size                522.96 GiB
  Current LE             133878
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

  --- Logical volume ---
  LV Path                /dev/pve1/backup
  LV Name                backup
  VG Name                pve1
  LV UUID                Fgz6TX-XCgo-9cH5-....
  LV Write Access        read/write
  LV Creation host, time proxmox, 2014-03-28 13:10:46 +0400
  LV Status              available
  # open                 1
  LV Size                250.00 GiB
  Current LE             64000
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:3

Free space is quite enough. /dev/pve1/backup have 230Gb of free space and on /dev/pve1/data 360Gb is available. May be the reason is small size of SWAP partition (only 7Gb)? If so - how can I extend it?

Thanks!

Solution

Well, the solution was hiding in size parameter of vzdump tool (it define value of allocated memory for snapshot). By default it set to 500 Mb (proxmox v3.0). Changing it to 4096 solved my problem.

It can be configured by adding the following line into /etc/vzdump.conf

size: 4096

Or directly in cron /etc/pve/vzdump.cron by adding --size 4096 key/value pair. Thanks.