WordPress provides tools to crop your images after you’ve uploaded them to your Media Library. To support this feature, you need to install the php5-gd library:
sudo apt-get install php5-gd
More info here.
Increasing media upload size for WordPress / PHP5
On a default WordPress 4.8 install on PHP5 the default file upload size seems to be (at least on my install) 2MB. If you’re uploading large image files or videos, it’s likely you’ll want to upload files much larger than this.
There’s a number of possible configuration locations that can control/configure the upload size. The first location is likely to be your php.ini file used by your apache or nginx. The settings to increase are:
- post_max_size (must be larger than upload_max_size)
- upload_max_filesize
- memory_limit
This article has a comprehensive walkthrough the possible configuration changes.
Comparing nginx memory usage to apache2
I’ve trimmed down my apache conf to work ok for a small site, but after uploading my exported data from my old site to my new, the 4x apache2 processes have grown considerably and consumed all my VPS memory. Knowing nginx has a much lighter footprint, I wondered what it would look like in comparison.
Here’s the memory usage after completing my exported data file imports – I get that after completing this imports to the new site this is the memory usage of the apache processes after load from importing about 20x 10MB xml export files. At idle after a restart the memory usage does start considerably lower, but here’s where I’m at right now:
$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r %MEM %CPU RSS VSZ COMMAND 32.2 1.7 169228 904300 /usr/sbin/mysqld 24.5 1.2 128684 385360 /usr/sbin/apache2 -k start 20.2 0.2 105968 355004 /usr/sbin/apache2 -k start 18.4 4.0 96740 352540 /usr/sbin/apache2 -k start 2.5 0.0 13144 283312 /usr/sbin/apache2 -k start
So following the guide here just to install nginx and the fastcgi php, and then here for WordPress specific config, here’s what it looked like on restart:
$ ps -eo pmem,pcpu,rss,vsize,args | sort -k 1 -r %MEM %CPU RSS VSZ COMMAND 9.3 0.4 49124 576488 /usr/sbin/mysqld 6.0 0.0 31516 235504 php-fpm: pool www 4.5 0.0 23860 232660 php-fpm: pool www 2.6 0.0 14032 230016 php-fpm: master process (/etc/php5/fpm/php-fpm.conf) 0.5 0.0 2804 86472 nginx: worker process 0.3 0.0 2004 86128 nginx: worker process 0.3 0.0 2004 86128 nginx: worker process 0.3 0.0 1988 86128 nginx: worker process 0.3 0.0 1900 33188 init 0.2 0.0 1452 85832 nginx: master process /usr/sbin/nginx
This is looking better, still need to work on getting the mysql usage down, but at least now I’m not maxed out:
$ free total used free shared buffers cached Mem: 524288 431192 93096 68180 0 259440 -/+ buffers/cache: 171752 352536 Swap: 0 0 0
Exporting WordPress content from one site and importing to a new site
WordPress has built in tools to export existing content which you can import into another WordPress site, but if you have a large site, you might run into this error when importing your exported data file:
Sorry, there has been an error. File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini or by post_max_size being defined as smaller than upload_max_filesize in php.ini.
There’s two parameters here that you can increase: upload_max_filesize and post_max_size. If you increase these, post_max_size should be larger than upload_max_filesize (more info here).
Next up, if you have a very large site, no matter how much you increase these params, they still might not large enough to upload a single export file. In which case, there are utilities to split the exported data xml into multiple smaller files. Here’s one example here I just and it seemed to work well.