On Sun, Dec 16, 2007 at 02:11:59PM -0800, SJS wrote:
A hardware RAID controller can write to each disk in parallel, computing the necessary checksums, etc., while a JBOD with a single controller will need to write to each disk separately (if the data is to span multiple disks).
Software RAID can do this as well, if you're willing to put each drive on a separate bus, and the OS and the rest of the architecture can handle it. You do have to compute checksums with one of the CPUs on the host. This becomes more of a problem with more complex parity algorithsm, such as RAID-6 uses.
That's not saying that hardware RAID controllers all *do* that; I would not be at all suprised to find out that some don't. But they *can* (and arguably *should*).
If _would_ surprise me if the cheap "RAID" boxes you can buy and drop drives in and appear as either a USB device, or a network share do things well. It would surprise me if they even worry about power-failure robustness. Dave -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
