Plesk backup task is failing: Cannot stat: Permission denied

Symptoms

• Plesk backup creation finished with one of the following messages in Plesk interface:

  PLESK_ERROR: Failed to pack files example.com_user-data_1307261006 in /var/lib/psa/dumps/domains/example.com
  /bin/tar: httpdocs/components/tmpForThumb: Cannot open: Permission denied
  /bin/tar: Exiting with failure status due to previous errors

  ---

  PLESK_WARN: Not all the data was backed up into /var/lib/psa/dumps/clients/cl_name/domains/example.com successfully.
  Mounted on: /. /bin/tar: .pki/nssdb: Cannot stat: Permission denied
  /bin/tar: Exiting with failure status due to previous errors

  ---

  PLESK_WARN: Warning: Subscription "example.com"
  Not all the data from /var/www/vhosts/example.com was backed up successfully:
  .cagefs/opt: Cannot open: Permission denied
  .cagefs/opt/alt: Cannot stat: Permission denied
  .cagefs/opt/alt/php56: Cannot stat: Permission denied
  .cagefs/opt/alt/php56/link: Cannot stat: Permission denied
  .cagefs/opt/alt/php56/link/conf: Cannot stat: Permission denied
  .cagefs/opt/alt/php73: Cannot stat: Permission denied
  .cagefs/opt/alt/php73/link: Cannot stat: Permission denied
  .cagefs/opt/alt/php73/link/conf: Cannot stat: Permission denied
  .cagefs/var: Cannot open: Permission denied
  .cagefs/var/run: Cannot stat: Permission denied
  .cagefs/var/run/cagefs: Cannot stat: Permission denied
  .cagefs/var/run/cagefs/utmp: Cannot stat: Permission denied

• Unable to restore a backup with the following message:

  PLESK_WARN: Warning: Restore hosting "example.com"
  Can not deploy content of domain example.com
  warning:
  Archive error: Unable to extract files from /var/lib/psa/dumps/domains/example.com/backup_user-data_1907081210.tgz to /var/www/vhosts/example.com: /usr/lib/plesk-9.0/sw-tar: example.com/bin/gzip: Cannot open: File exists /usr/lib/plesk-9.0/sw-tar: example.com/bin/unzip

  ---

  PLESK_WARN: Warning:
  Archive error: Unable to extract files from /var/lib/psa/dumps/domains/example.com/backup_user-data_1907311520.tgz to /var/www/vhosts/example.com: /bin/tar: httpdocs/some-picture.jpg: Cannot open: File exists /bin/tar: httpdocs/wp-content/uploads/2019/some-picture.jpg: Exiting with failure status due to previous errors

• Multiple file and folders have root permissions under the subscription folder /var/www/vhosts/example.com

Cause

Incorrect file or directory permissions for virtual host directories located at /var/www/vhosts/example.com.

Resolution

1. Connect to the server via SSH.

2. Correct the file permissions:

   # plesk repair fs example.com

3. If the command from the 2nd step does not help, restore default ownership and permissions for /var/www/vhosts/example.com:

   In the case of one affected domain, the permissions can be restored following the steps on this article: How to restore default permissions in the virtual host directory on Linux?

   Note: In case more than one domain is affected, fix the permissions issue for all affected domains. In this case, the following can be performed:

   # plesk db -Ne "select login,home from sys_users where mapped_to is null" | while read login home; do chown -R $login $home; done

Additional information

Backup task has finished with a warning: Cannot open: File exists /bin/tar