Messages in this thread | | | Date | Sat, 18 May 2002 13:47:50 +0100 | From | "Stephen C. Tweedie" <> | Subject | Re: Thoughts on using fs/jbd from drivers/md |
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Hi,
On Fri, May 17, 2002 at 06:35:37PM -0700, Mike Fedyk wrote: > On Fri, May 17, 2002 at 07:34:10PM +0100, Stephen C. Tweedie wrote: > > Degraded mode relies on the parity disk being in sync at all times --- > > Doesn't degraded mode imply that there are not any parity > disk(raid4)/stripe(raid5) updates?
Nope, partity updates still occur. It's more expensive than in non-degraded mode, but parity still gets updated. If it wasn't, you would not be able to write to a degraded array at all, as updating parity is the only way that you can write to a block which maps to a failed disk. By using parity, we only ever fail requests if there are two or more failed disks in the array.
Cheers, Stephen - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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