All my servers have an 8 GB empty file on disk
I've been doing this for years too.  I also learned instead of one big file, halving several files is also useful so you can release space in "chunks".  If you need everything at once you can wildcard the delete.<p>Such flexibility has been invaluable over the years.  Thankfully with block storage and modern operating systems/file systems growing volumes can be significantly easier for most servers.