When creating a file system (
mkfs ...) the file system reserves 5% of the space for its own use because, according to
Reserving some number of filesystem
blocks for use by privileged processes
is done to avoid filesystem
fragmentation, and to allow system
daemons, such as syslogd(8), to
continue to function correctly after
non-privileged processes are prevented
from writing to the filesystem.
But with large drives 5% is quite a lot of space.
I have 4×1.5 TB drives for data storage (the OS runs on a separate disk), so the default setting would reserve 300 GB, which is an order of magnitude more than the the entire OS drive.
The reserved space can be tweaked, but what is a reasonable size for a data disk? Can I set it to zero, or could that lead to issues with fragmentation?