Messages in this thread | | | Date | Mon, 22 Jan 2001 21:28:27 -0200 | From | Andrew Clausen <> | Subject | Re: Partition IDs in the New World TM |
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Russell King wrote: > > Andrew Clausen writes: > > Why is this necessary? Can't the RAID drivers probe the device for > > signatures, the same way file systems do? > > One possible problem I can see here is to do with removal of RAID. Think > of a RAID-1 array (2 or more disks containing identical data). The > partition can be validly identified as an ext2 filesystem. But wait, it > has a RAID superblock at the end. > > How do we know if this superblock is current or not? After all, a mke2fs > on the device won't remove it. Yes, you could fill the partition with > zeros and start again, or you could just change the partition ID.
Yeah, this is a big problem.
Parted solves it, by defining a clobber() operation for each file system type (which can/should be extended to RAID, if/when we get around to supporting it properly). clobber() removes all signatures.
So, I guess the short answer is: mke2fs should remove the RAID super. For those of you who don't like all-in-one libraries like libparted - not mentioning any Christo^Wnames - you could probably have clobber.ext2, etc.
However, you would want to have a comprehensive set of clobber.*. Fortunately, clobber.X is going to be very small, so this should be a problem.
So, the alternative is to define a RAID partition "data" type. (And forget about IDs for file systems)
Andrew Clausen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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