I wasn't able to load very large (>2Mb) import files via the Zabbix GUI. Turns out PHP was limiting the size of the uploads.
I changed /etc/php.ini from:
; Maximum allowed size for uploaded files.
upload_max_filesize = 2M
to:
; Maximum allowed size for uploaded files.
upload_max_filesize = 64M
I also had to set these var really high:
max_execution_time = 900 ; Maximum execution time of each script, in seconds
max_input_time = 60 ; Maximum amount of time each script may spend parsing request data
memory_limit = 512M ; Maximum amount of memory a script may consume
I changed /etc/php.ini from:
; Maximum allowed size for uploaded files.
upload_max_filesize = 2M
to:
; Maximum allowed size for uploaded files.
upload_max_filesize = 64M
I also had to set these var really high:
max_execution_time = 900 ; Maximum execution time of each script, in seconds
max_input_time = 60 ; Maximum amount of time each script may spend parsing request data
memory_limit = 512M ; Maximum amount of memory a script may consume