Plesk backup fails with error: Not enough free disk space to backup selected objects

Symptoms

• Backup fails with one of the following errors in Plesk UI:

  PLESK_ERROR: Not enough free disk space to backup selected objects. At least 60862Mbytes free disk space is required.

  ---

  PLESK_ERROR: Error: server "server"
  Cannot encrypt dump file (this is not fatal error!): Error occured while sending feedback. HTTP code returned: 500 Error occured while sending feedback. HTTP code returned: 500 DB query failed: SQLSTATE[HY000]: General error: 1030 Got error 28 from storage engine, query was: DESCRIBE `clients`

• When creating backup from command-line interface using pleskbackup utility, dump is deleted without clear message in /var/log/plesk/PMM/pmmcli.log:

  CONFIG_TEXT: DEBUG: We are going to delete incompleted backup from local storage backup_info_1711271102.xml 
  DEBUG: Executing asynchronously [25566] process. CmdLine is '/usr/local/psa/admin/bin/pmm-ras --delete-dump-files --dump-storage=/var/lib/psa/dumps --dump-file-specification=backup_info_1711271102.xml --session-path=/usr/local/psa/PMM/sessions/2017-11-27-110256.247' 
  ... 
  INFO: Outgoing packet: 
  <?xml version="1.0" ?><response> 
  <errcode>0</errcode> 
  <data> 
  <task-status task-id="10"> 
  <finished log-location="/usr/local/psa/PMM/sessions/2017-11-27-110256.247/migration.result" status="error"> 
  </finished> 
  </task-status> 
  </data> 
  </response>

Cause

There is not enough disk space on the server.

Resolution

1. Connect to the server via SSH or via RDP
2. Increase the disk space on the server or free some space.

3. Execute the following command in order to update Plesk Usage with the new disk space:

   # plesk daily ExecuteStatistics