> It all boils down to having to cope with individual units' > limits and failures. > > If a file needs to be larger than the capacity of the largest > disk, you stripe data across multiple disks. To handle disk > failures you use mirroring or parity across multiple disks. > To increase performance beyond what a single controller can > do, you add multiple disk controllers.
striping, mirroring, etc really don't need to affect the file system layout. ken fs, of course, is one example. the mirroring or striping is one example. in the case of ken fs on aoe, ken fs doesn't even know at any level that there are raid5s down there. same as with a regular hba raid controller. since inside a disk drive, there is also striping across platters and wierd remapping games (and then there's flash), and i don't see any justification for calling this a "different fs layout". you wouldn't say you changed datastructures if you use 8x1gb dimms instead of 4x2gb, would you? - erik
