In my site host, I have seen (via phpinfo) that
- post_max_size = 8Mb
- upload_max_filesize = 16Mb
This led me to think that I should be able to upload as file as big as 16Mb. However, when I do this through a post method (as normal), post_max_size takes over and declares that I sent too much.
What is the method which permits sending a file as big as 16Mb ? GET - PUT - other ?
Hope someone can clarify this for me.
Simon
upload_max_filesize is the limit of any single file.
post_max_size is the limit of the entire body of the request, which could include multiple files.
Given post_max_size = 20M and upload_max_filesize = 6M you could upload up to 3 files of 6M each. If instead post_max_size = 6M and upload_max_filesize = 20M then you could only upload one 6M file before hitting post_max_size. It doesn't help to have upload_max_size > post_max_size.
It's not obvious how to recognize going over post_max_size. $_POST and $_FILES will be empty, but $_SERVER['CONTENT_LENGTH'] will be > 0. If the client just didn't upload any post variables or files, then $_SERVER['CONTENT_LENGTH'] will be 0.
By POST file uploads are done (commonly, there are also other methods). Look into the method attribute of the form which contains the file-upload field ;)
The lowest limit of any related setting supersedes a higher setting:
See Handling file uploads: Common Pitfals which explains this in detail and how to calculate the values.
The normal method to send a file upload is POST, thus also post_max_size should be 16 Mb or more.
Incidentally, also memory_limit plays a role. It should be bigger than 16Mb, but since the default value is 128Mb, you won't see this problem. Example php.ini configuration:
post_max_size = 16M
upload_max_filesize = 16M
memory_limit = 128M
Change these value in php.ini if you've access to it, otherwise you can try to change them in an .htaccess file.
php_value upload_max_filesize 16M
php_value post_max_size 16M
This will work only if the AllowOverride settings permit it. Otherwise, you've to ask to your hosting company.
Your server configuration settings allows users to upload files upto 16MB (because you have set upload_max_filesize = 16Mb) but the post_max_size accepts post data upto 8MB only. This is why it throws an error.
Quoted from the official PHP site:
To upload large files, post_max_size value must be larger than upload_max_filesize.
memory_limit should be larger than post_max_size
You should always set your post_max_size value greater than the upload_max_filesize value.
post_max_size:
- Sets max size of post data allowed. This setting also affects file upload
- To upload large files, this value must be larger than upload_max_filesize
- Generally speaking, memory_limit should be larger than post_max_size.
- PHP Default: 8M
upload_max_filesize:
- The maximum size of an uploaded file
- PHP Default: 2M
memory_limit > post_max_size > upload_max_filesize
PHP Default: 128M > 8M > 2M
By default, post_max_size should be 4 times greater than upload_max_filesize.
In turn
memory_limit should be 16 times greater than post_max_size
change in php.ini max_input_vars 1000
来源：https://stackoverflow.com/questions/7754133/php-post-max-size-overrides-upload-max-filesize