I did some testing, I am backing up the following:
[quote]/home/user/domain.com - html, php, flash, images - 5.4MB Un-compressed / 5.5MB Tar’ed
/home/user/store.domain.com - Magento Store - 160.3MB Un-compressed / 203.3 Tar’ed
mysql.sql - Magento MySQL DB - 2.5MB un-compressed[/quote]
Total = 168.2MB Un-Compressed / 211.3MB Tar’ed (including un-tared mysql)
I tar’ed the .com and the store so that I could preserve permissions, but it’s pretty funny to notice that by doing that I actually increased the size of the files by 2% and 21% respectively. I didn’t Tar the mysqldump because there wasn’t a need to preserve permissions.
Anyways on to the results:
[quote]gzip = 64.8MB = 70% compression
bzip2 = 58.2MB = 73% compression
7z = 42.6MB = 80% compression[/quote]
So all in all, it’s not that much of a savings to use 7z over gzip for web site related backups. While I didn’t time the compression or CPU usage, I know for a fact 7z is a resource hog, so it doesn’t surprise me that Dreamhost doesn’t have it enabled. I just had to ask.