Support » Plugin: BackWPup - WordPress Backup Plugin » Not playing well with W3 Total Cache?

  • Resolved audvin


    I get this error on any jobs I create (even a simple optimize db job).

    [INFO] BackWPup version 3.0.5; WordPress version 3.5.1; A project of Inpsyde GmbH developed by Daniel Hüsken
    [INFO] This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions.
    [INFO] BackWPup job started manually
    [INFO] PHP ver.: 5.3.20; apache2handler; Linux
    [INFO] Maximum script execution time is 200 seconds
    [INFO] MySQL ver.: 5.0.77-log
    [INFO] curl ver.: 7.15.5; OpenSSL/0.9.8b
    [INFO] Temp folder is: /mnt/asdf/backwpup-e22fc-temp/
    [INFO] Logfile folder is: /mnt/asdf/backwpup-74c92-logs/
    [INFO] Backup type is: archive
    [12-Mar-2013 14:16:24 America/Chicago] PHP Warning: Division by zero in /mnt/asdf/wp-content/plugins/w3-total-cache/lib/W3/PgCacheFlush.php on line 389
    [12-Mar-2013 14:16:24 America/Chicago] PHP Warning: Division by zero in /mnt/asdf/wp-content/plugins/w3-total-cache/lib/W3/PgCacheFlush.php on line 389
    [12-Mar-2013 19:16:24] DEPRECATED: Assigning the return value of new by reference is deprecated
    [12-Mar-2013 14:16:24 America/Chicago] PHP Fatal error: Class ‘BackWPup_Option’ not found in /mnt/asdf/wp-content/plugins/w3-total-cache/lib/W3/PgCacheFlush.php on line 389

    What would be the reason for this?


Viewing 6 replies - 1 through 6 (of 6 total)
  • We’re still seeing this error whenever we try to backup. The backup simply fails.

    Plugin Author Daniel Hüsken


    The Plugin calls the W3TC functions to flush cache.
    What happends when you clean the cache by hand?

    Here is what I have found when both BackWPUp and W3 Total Cache are activated:

    WordPress version 3.5.1
    BackWPup version 3.0.8 Get pro.
    PHP version 5.3.13
    MySQL version 5.1.39-log
    PHP Memory limit 90M
    WP memory limit 40M
    WP Maximum memory limit 256M
    Memory in use 57.75 MB

    W3 Total Cache: v0.9.2.9

    Database only backup to a Folder – All tasks complete OK
    Database only backup to e-mail – All tasks complete OK
    Database only backup to FTP – Database dump completes OK. Archive creation completes OK. Connection to FTP server completes OK, but only part of file is transferred to the FTP server before we see:

    [17-Apr-2013 22:29:06 UTC] PHP Fatal error: Allowed memory size of 94371840 bytes exhausted (tried to allocate 445825 bytes) in /home/username/ on line 211

    I also tried to purge all caches manually immediately before running BackWPUp – same result and failure at same point.

    I have disabled W3 Total Cache for now until a workaround can be found (BackWPUp works flawlessly doing file/database backups when W3 Total Cache is not activated).

    Thank you.


    Plugin Author Daniel Hüsken


    Try with the WP_MAX_MEMORY_LIMIT that will used on executing jobs.


    Yes, it is definitely a memory issue. I removed some other plugins and re-ran my database backup job and it worked OK. The WP_MAX_MEMORY_LIMIT was already set at 256MB, but the PHP MEMORY_LIMIT is at 90MB and that seems to be the limiting factor. I cannot increase that limit in my current shared hosting environment, so I will have to figure out which plugins I can either tune or not use.


    FWIW, W3TC has a bug right now that does not clear cache so the cache folder is HUGE. Best thing would be to exclude the W3TC cache directory all together.

Viewing 6 replies - 1 through 6 (of 6 total)
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