Mdadm -- Raid-10

[BillT440]

I want to create a software raid-10 array. I'm not certain on is the actual syntax (maybe best practices is a better term) to create the raid-10. What I can't find documented anywhere is whether or not the the array wants to be constructed of of other md devices or is it intuitive enough to just give it raw disks?

examples

mdadm -C /dev/md0 --level=10 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

or

mdadm -C /dev/md0 --level=0 --raid=devices=2 /dev/sda /dev/sdb
mdadm -C /dev/md1 --level=0 --raid=devices=2 /dev/sdc /dev/sdc
mdadm -C /dev/md2 --level=10 --raid=devices=2 /dev/md0 /dev/md1

Both ways seem to work as far as constructing the array goes. What do you guys think?

Thanks in advance,

Bill

I think your commands may error if you are specifying a whole disk rather than partitions. I would think it better to create a parition on each disk (unformatted and spanning the entire volume):

mdadm -C /dev/md0 --level=0 --raid=devices=2 /dev/sda1 /dev/sdb1

Also, I don't think mdadm understands raid-10, so you'll have to use the second method you outlined.