Backup of Very Large Filesystems and Files
Large filesystems and files caught many backup products by surprise. For many years, 4 GB filesystems with a maximum of 2 GB files
ruled the land. This is because none of the operating systems allowed anything larger.
Then came 32-bit and 64-bit operating systems and the multiterabyte filesystem. Not long
after that, some vendors were announcing the ability to create multiterabyte files. This
caused a major problem with some backup vendors because many design decisions were made
assuming there was a 4 GB limit.
It’s inexcusable that a product would still have this problem at this point.
There are a few things to consider when investigating whether a given product can
handle large files and filesystems. Does the vendor have any hardcoded limits that say a
file can’t be any bigger than N bytes? Do they have problems if a filesystem (or file) is
bigger than a volume? Do they have any automated way to create multiple simultaneous
backups of a single filesystem, without requiring you to manually divide that filesystem
into many pieces?