This file isn't a part of standard Magento. Based on the comments posted it sounds like someone, at one time, configured PHP (either via
php.ini or via a call to
ini_set) to log its errors to this file. It's also possible that your web server (Apache or nginx, most commonly) is configured to use this file as an error log. (as PHP errors are passed along to the webserver's error logs)
From a technical perspective you should be able to safely remove this file. I would
- Make note of the unix permissions on this file
- Use the
mv command to move this file elsewhere on disk. A
mv should be a quick operation, even for a large file
- Create a new file with the same name in the same spot. Make sure this file has the same unix permissions from #1.
If something explodes when you move the file, move it back. If nothing explodes you can delete the file or back it up somewhere off your server.
Monitor the new file you created. If its growing regularly then I'd look into setting up your system to regularly rotate this file with a command like
logrotate. This command will gzip you logs for storage and then zero out the actual file. This is usually enough to control disk size.
I'd also suggest you address any PHP errors cropping up in the logs -- but I know how priorities usually go there.