This guide is helpful to resolve receiving error emails like this:

To fix the issue, is necessary to create a file that contains the script as we describe on the next step by step instructions

1. Login SynetoOS from SSH and insert the following

2. sudo su

3. Copy the code above and paste it in /usr/sbin/perform_backup

4. #!/usr/bin/php
   <?php
   if (!isset($argv[2])) {
       exit(3);
   }
   
   require_once('Lego/autoload.php');
   
   $svcId = $argv[2];
   $serviceRepo = new \Backup_ServiceRepository(new \Backup\SystemServiceFactory());
   if (!$serviceRepo->findByIdentifier($svcId)) {
       exit(2);
   }
   
   $snapshotPerformer = new Backup_Performer();
   $snapshotPerformer->setServiceIdentifier($svcId);
   $snapshotPerformer->setSnapshotPath($argv[1]);
   $withVirtualMachines = !$argv[3] || $argv[3] == 'true';
   
   try {
       $snapshotPerformer->perform($withVirtualMachines);
   } catch (Exception $e) {
       // HACK
       // the progress content is persisted using priv_writer which spawned as a child process
       // we need to wait for the progress to be written before we exit
       // SEE STORAGE-2339 
       $status = null;
       pcntl_wait($status);
       exit(1);
   }

   
   

5. cat > /usr/sbin/perform_backup

   (paste it and ctrl + c after)