Defining the PHP memory_limit

If you get a message like this one,

"Allowed memory size of 536870912 bytes exhausted (tried to allocate 13743895345 bytes) at DOCROOT/lib/private/image.php#xxx"

it is likely that you have a PHP memory_limit set too low for your needs. Image processing requires a lot of memory.

Here is a quick Bytes to MegaBytes conversion table to make more sense out of these large numbers

Bytes	MegaBytes
8388608	8
16777216	16
33554432	32
67108864	64
134217728	128
268435456	256
536870912	512
1073741824	1024

Understanding your requirements

In order to understand what your memory requirements might be, you should visit this website which lets you input an image's dimensions and the target size and will calculate how much memory the operation will require:

http://www.dotsamazing.com/en/labs/phpmemorylimit

Some examples

MegaPixel	MegaBytes
14.1	99
12.2	87
8.7	66

All those numbers are on top of what the process is already using for its normal operation 30-60MB

Adjusting the limit

Please refer to the ownCloud documentation to understand where you should modify the PHP memory_limit setting:

https://doc.owncloud.org/server/8.2/admin_manual/configuration_files/big_file_upload_configuration.html#configuring-php

Note: The syntax is different depending on where you make the modification.