Our backup uses 3 mechanisms to take the backup

  1. Command line - Fast and sometimes takes more memory
  2. PHP Zip - Slow and takes less memory than command
  3. PCLZip - Slow and takes way less memory than both

Some servers disable Command Line / PHP Zip, there by causing the backup to take more time and fail.

Backup fails mainly due to less memory allocated to the server and PHP / Webserver times out before the operation is completed. 

If the the backup fails due to memory limit with 500 error / memory exhaust error, add these lines to your .htaccess of your WP site  
php_value memory_limit 256M


Or edit these values in your php.ini of your WP site

 

memory_limit = 256M

 


If it still fails, try enabling Fail-safe options


First check [ ] Files and try backing up. If that also fails, check both [ ] Files & [ ] DB and try again.

With this setting if the backup still fails, try increasing the timeout for your PHP & Webserver.


Add these lines to your .htaccess of your WP site to increase PHP timeout 

 

php_value max_execution_time 800

 


Or edit these values in your php.ini of your WP site to increase PHP timeout 

 

max_execution_time = 800