Article ID: 118134, created on Oct 23, 2013, last review on Jun 17, 2016

  • Applies to:
  • Virtuozzo
  • Virtuozzo hypervisor

Symptoms

Incremental backups fail for a specific Virtual Machine:

~# prlctl backup "VM name"
Failed to backed up the VM: Failed to back up the virtual machine due to an internal error. Please try again. If the problem persists, contact your system administrator for assistance.

Cause

One of the previous backups in the chain of incremental backups is missing, or corrupt. Below you can find several scenarios when corruption is reported by PSBM (note that all commands are executed inside of the backup's folder):

~# pwd
/vz/vmprivate/backups/{9ed4f97a-68b0-4742-8969-160cf690b7c5}/{f4ed1128-7a45-45fa-99d8-0dd9477ab546}

Where

  • /vz/vmprivate/backups/ is a default backup location (can be checked in the output of the command: prlsrvctl info | grep ^Backup:);
  • {9ed4f97a-68b0-4742-8969-160cf690b7c5} is a VM's UUID;
  • {f4ed1128-7a45-45fa-99d8-0dd9477ab546} is a full backup's ID.

Scenarios when PSBM will consider backup as corrupted:

  1. .metadata files point to non-existent tib file

    ~# grep tib */.metadata
    2/.metadata:   <TibFileList>harddisk.hdd2.tib</TibFileList>
    3/.metadata:   <TibFileList>harddisk.hdd3.tib</TibFileList>
    base/.metadata:   <TibFileList>harddisk.hdd1.tib</TibFileList>
    ~# find *.tib
    harddisk.hdd2.tib
    harddisk.hdd.tib
    

    In the example above harddisk.hdd3.tib is missing.

  2. .metadata files point to the same tib file

    ~# grep tib */.metadata
    2/.metadata:   <TibFileList>harddisk.hdd2.tib</TibFileList>
    3/.metadata:   <TibFileList>harddisk.hdd2.tib</TibFileList>
    base/.metadata:   <TibFileList>harddisk.hdd1.tib</TibFileList>
    ~# find *.tib
    harddisk.hdd2.tib
    harddisk.hdd3.tib
    harddisk.hdd.tib
    

    In the example above harddisk.hdd2.tib is referenced by two .metadata files simultaneously.

  3. Some .tib file(s) are not referenced by any .metadata file

    ~# grep tib */.metadata
    2/.metadata:   <TibFileList>harddisk.hdd2.tib</TibFileList>
    base/.metadata:   <TibFileList>harddisk.hdd1.tib</TibFileList>
    ~# find *.tib
    harddisk.hdd2.tib
    harddisk.hdd3.tib
    harddisk.hdd.tib
    

    In the example above harddisk.hdd3.tib is not referenced by any .metadata file.

Resolution

Some scenarios when backup might get corrupted are fixed in PSBM 5 Update 9 Hotfix 2.

Additional checks for the backup corruption will be added into "prlctl backup" in the future in scope of the internal request PSBM-21679.

In order to create a new backup successfully you'll have to start a new backup chain - force the creation of a full backup:

~# prlctl backup "VM name" --full

Search Words

prlctl backup

fails

backup

internal error

incremental

Failed to backed up the VM

PSBM-21679

a26b38f94253cdfbf1028d72cf3a498b 2897d76d56d2010f4e3a28f864d69223 0dd5b9380c7d4884d77587f3eb0fa8ef

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