Article ID: 112397, created on Sep 28, 2011, last review on May 7, 2014

  • Applies to:
  • Virtuozzo containers for Linux 4.7
  • Virtuozzo containers for Linux 4.6
  • Virtuozzo containers for Linux 4.0


Backup of a large container fails after several hours of execution:
[root@hwnode ~]# vzabackup -F localhost -e 
Starting backup operation for node ''...
* Operation with the Container is started
* Backing up environment locally
* Checking parameters
* Creating backup 4d913d6a-4f1c-674c-b91a-c9eef9082a74/20110706094115
* Adjusting backup type (full)
* Backup storage: receiving backup file
* Preparing for backup operation
* Snapshots are not created, continuing backup...
* Backing up private area
* Operation with the Container is finished with errors: Connection to vzagent was closed.
Backup operation for node '' failed: Connection to vzagent was closed
Backup failed
[root@hwnode ~]#

Timeouts for backup operations are large enough (up to 10 hours). Parallels Containers installation is up-to-date.


Most likely the operating system of the server is 32-bit, and the amount of disk nodes occupied by a container exceeds 2 million in value:
[root@hwnode ~]# vzquota stat 1234
   resource          usage       softlimit      hardlimit    grace
  1k-blocks       56852432       209715200      230604800
     inodes        9518734        20000000       22000000
[root@hwnode ~]# uname -m


Such large containers should be hosted only on 64-bit nodes. The backup with vzabackup for those containers cannot be created on 32-bit nodes.

Currently, during a backup operation, the process needs 1.5kb per node used by the files of a container. With the 32-bit system, any process is limited to 3GB of address space, and this limits the amount of memory which can be used for storing information about nodes during the backup operation.
With more than 2 million nodes, this architectural limit is hit and the process fails with a segmentation fault, producing output similar to a case with insufficient timeout.

Migrate the container to the 64-bit hardware node to get rid of the issue.

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