md arrays can be partitioned just like other block devices (2.6)
This is useful for...
-a|--auto option in the mdadm man page for full details.
Simply create your array like this:
mdadm --create /dev/media ... --auto p4
which tells mdadm to automatically create 4 partitions (it defaults to 5).
and mdadm will create:
/dev/media /dev/media1 /dev/media2 /dev/media3 /dev/media4
mdadm has a set of 'standard' formats which it uses to guide its behaviour when creating device files via the --auto option.
The standard names for non-partitioned arrays (the only sort of md array available in 2.4 and earlier) either of
where NN is a number. The standard names for partitionable arrays (as available from 2.6 onwards) is one of
Partition numbers should be indicated by added "pMM" to these, thus "/dev/md/d1p2".