Remote backups are created with error: The size of the volume does not match the expected one

Symptoms

• Remote backups are created with an error

  Error:
  Export error: The size of the volume backup_0000000000.tar2 2146421760 does not match the expected one 2146435072. The remote backup may not be restored.
  Error:
  Unable to validate the remote backup. It may not be restored. Error: Unable to extract dump header

• The following entries are logged to backup.log in /var/log/plesk/PMM/backup-<datetime> or %plesk_dir%PMMlogsbackup-<datetime>

  Curl error: (28) Timeout was reached: Last FTP request: STOR backup_0000000000.tar2: Last FTP response: 150 Ok to send data
  Curl output: > SIZE backup_0000000000.tar2
  Curl output: > APPE backup_0000000000.tar2
  ExportError Export error: The size of the volume backup_0000000000.tar2 2146421760 does not match the expected one 2146435072. The remote backup may not be restored. [common/plesk-utils/PMM/pmm-ras/pmm-ras.cpp:ExportError]

Cause

A reused connection timed out before the backup could be completed.

Resolution

1. Edit panel.ini

2. Add the following section to turn off connection reuse

   [pmm]
   ftpForbidReuseConnection = 1

3. Save the changes