You can always mount your third partition somewhere (like /mnt/combo
or something), and then bind-mount subdirectories from this mountpoint to the three designated directories.
In fstab
, this would look something like
UUID=... /mnt/combo auto defaults
/mnt/combo/usr /home none bind
/mnt/combo/var /var none bind
/mnt/combo/home /home none bind
Also consider this: /home
makes sense to live on a separate partition - even better, a separate drive, which can be somehow protected (raid, backups,...). /var
would make sense to be separate if you really have something personal in there (websites and such), otherwise it makes no difference. /usr
can definitely be part of /
, it makes no sense to have it separate because on a modern system, the distinction between /bin
and /usr/bin
is blurred and noone cares about it anymore, and segmenting a system only creates problems if one of the partitions somehow doesn't mount.
/tmp
should normally be ram-backed anyway (tmpfs
), unless you really are running out of RAM, and most distros do that by default unless you change it.
Big picture: separate /home
if you have to, the rest is just overhead - you probably have no reason to have different filesystem types or different permissions on any of these, and partitioning doesn't usually mean physical separation (same hard drive?).
/
and/usr
anymore. You can't do reinstalls leaving/usr
untouched either (and/var
not completely).