Article ID: 119231, created on Dec 19, 2013, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo
  • Virtuozzo containers for Linux
  • Virtuozzo hypervisor
  • Virtual Automation


There are several *DemonData.swap* files inside /vz/tmp directory of different size, and they can be quite huge:

[root@vz ~]# du -sh /vz/tmp/*
914M    /vz/tmp/0GED89RO~DemonData.swapFile.dat~
4.0K    /vz/tmp/4SDLCJQ6~DemonData.swapFile.dat~
48G     /vz/tmp/AGGN9R9C~DemonData.swapFile.dat~
48G     /vz/tmp/EHRTKJQO~DemonData.swapFile.dat~
4.0K    /vz/tmp/HDJ10P04~DemonData.swapFile.dat~
4.0K    /vz/tmp/I4QHRLSF~DemonData.swapFile.dat~
914M    /vz/tmp/I7PALN4D~DemonData.swapFile.dat~
4.0K    /vz/tmp/IT086FP8~DemonData.swapFile.dat~

Where do these files come from and is it safe to delete them to free up the disk space?


These files are created temporarily by Acronis backup engine (vzabackup utility) and store the file system B-tree of the container being backed up. The size may grow large, in case the container has a huge amount of files or a lot of files change dynamically during the backup operation.


Ensure that no process is currently using the file:

[root@vz ~]# lsof /vz/temp/I7PALN4D~DemonData.swapFile.dat~
[root@vz ~]#

Now it can be safely deleted.

In case the file is still being used by a vzlpl process, it's advised to wait until this backup operation finishes gracefully and removes the file automatically.

Additional information

Sometimes it is possible to locate and fix the reason why a container has a big amount of files.

Here's a real-life example:

  1. Container 101 has a great amount of inodes:

    [root@vz ~]# vzlist -o veid,diskinodes 101
          CTID   DQINODES
           101    1415838
  2. Find out what uses so much files inside the container. The most likely candidate is usually /var directory:

    [root@vz ~]# find /vz/root/101/var | wc -l
  3. Checking directories hierarchically, this can be narrowed down to a single directory, containing a lot of files:


    In this case, the directory stores temporary Apache PHP session files, which are not getting cleaned up and keep spawning eternally. The amount is too huge for a simple rm -rf * command, it will error out with "The argument list is too long". The methods to delete such a big amount of files can be found here: Deleting tons of files in Linux

  4. Once all files are deleted, the backup operation should not create any large temporary files inside /vz/tmp directory.

NOTE: It is highly advised to keep PVA Agent up-to-date, subscribe to PVA Builds & Releases article to keep track of the new releases.

NOTE2: /vz/tmp is the default directory for storing temporary Acronis files, but it can vary, depending on the version of PVA Agent.

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