> Or you can create raid0 with partitions on both drives (sda1+sdb1) > and "mirror" it on the second set of partitions on the same drives. > But then you do not have any protection from total disk failure > you'd normally expect from raid1. Only some very little protection > against a sector failure. > > Plus two equally strange configurations where you first create > raid1-mirrors and then strip them to raid0. Doing raid10 (or raid01) > with only 2 disks is imho not a good idea...
It is very well written everywhere that deals with raid that it is a very bad practice to have more than one raid device per drive AND per bus. Having two identical disks and a need for redundancy calls for raid1 (mirror), nothing else. Or anything else is just fancy crap, but hey, you can learn a lot with fancy crap. If you wish to get something a little more than raid1, it might be with raid6: partition each drives in 2 equal sized partitions, then create the raid6 on those 4 devices. You loose both reading and writting performance due to seeking from one partition to another, but you keep redundancy since with raid6, 2 device failures can happen. The advantage here, is scalability: you buy a third drive later, partition it correctly and 'grow' your raid6 on those 2 new devices. But even then, if you buy a 3rd drive, i'd recommend raid5 simply on the whole disks (well one partition per drive). Here, do whatever scenario you want, and when you buy a 3rd disk: fail and remove the secondary drive on current raid create a raid5 with the new drive and the removed spare and 'missing' copy old raid over to new raid fail old raid and add its device to the new raid update your /etc files to point to the new raid Enjoy!
