Increasing the maximum post size
Solution 1:
There are 2 different places you can set it:
php.ini
post_max_size=20M
upload_max_filesize=20M
.htaccess / httpd.conf / virtualhost include
php_value post_max_size 20M
php_value upload_max_filesize 20M
Which one to use depends on what you have access to.
.htaccess will not require a server restart, but php.ini and the other apache conf files will.
Solution 2:
I had a situation when variables went missing from POST and all of the above answers didn't help. It turned out that
max_input_vars=1000
was set by default and POST in question had more than that. This may be a problem.
Solution 3:
; Maximum allowed size for uploaded files.
upload_max_filesize = 40M
; Must be greater than or equal to upload_max_filesize
post_max_size = 40M