| gabriel rosenkoetter on 5 Oct 2006 23:16:36 -0000 |
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On Mon, Oct 02, 2006 at 12:54:59PM -0400, Will Dyson wrote: > A while back, I remember seeing a proposal for a standardized on-disk > format for hardware and software raid. I had thought that the major > vendors were on-board with the idea, but I haven't heard anything > since (from card vendors or the Linux MD/DM maintainers). Care to reference a url on that? I am inclined to find any such proposition laughable at best. The idea that you could do this and have the format be bootable on even two of the hardware architectures where the card was useable is a support nightmare, if even technically feasible. I routinely use same-spec PCI cards in i386, macppc, and sparc64 systems and, if I had any, would want to be able to in an Intel-based mac. For those specific examples, this can be a bit clumsy (since made-for-i386 PCI cards don't present themselves terribly well to OpenFirmware), but it works plenty well enough, even for devices providing storage resources. Saying that your PCI-compliant device is useable only on a subset of systems with standard-compliant PCI busses is a really good way to get horrible industry press, even though it's not logically unreasonable. Granted, my 3ware 9000-series RAID controllers are in an i386 machine running FreeBSD with drivers and management interface provided by the (card's) vendor, but if I were willing to go off in the rough and write my own drivers and management interfaces to their (published) API, I would fully expect that they didn't do anything assinine with bit order (or anything else) that would make them non-functional (or even just non-bootable) on a system with a different hardware architecture than they'd anticipated. I find it highly dubious that anybody would get all vendors producing computers with PCI busses to sign on to such a standardization unless it were codified as part of PCI, where it really, really doesn't belong. Never mind that even if the choices made at the time seemed like a good idea for an on-disk format, locking into that prevents people from devising more efficient methods. The job of a device providing RAID is to take my bits and give them back to me, providing redundancy in one of several ways defined at the logical level, not at the physical level. Forcing a physical standard on such devices is broken thinking. -- gabriel rosenkoetter gr@eclipsed.net Attachment:
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