On 01/22/2010 11:01 AM, Carlos E. R. wrote:
On Friday, 2010-01-22 at 17:23 +0100, Anders Johansson wrote:
...
As far as I know, fsck never does badblock analysis
As a matter of fact, it does. Kind of. For instance, for ext3 it calls e2fsck, and this one has options for badblock handling.
-- Cheers, Carlos E. R.
There in lies an Achilles' of dmraid that I am interested in. If there isn't a specific kernel level workaround to temporarily disable a dmraid array to check and correct any normally easily correctable 'disk' errors such as bad blocks, etc.., then that means a dmraid setup will suppress/prevent the correction of disk errors on each 'disk' in the array allowing simple correctable errors to propagate or grow into multiple compounded errors resulting in disk deterioration to the point of data loss. Simply put, if small disk errors go uncorrected in the dmraid array and are allowed to remain uncorrected and multiply, then dmraid has a gaping hole in its robustness making it look far inferior to software raid. I can't believe that it the way dmraid works. In the past, I have actually preferred it to software raid because I can rebuild a new disk following a drive failure and remake the array before I ever have to boot the operating system. But, if you can never e2fsck -fcy /dev/sda, sdb, etc.. without first disabling the array in the bios, you are basically playing Russian roulette with disk errors on any single disk in the array. Does anybody know more or have any links to detailed information on how bad blocks are handled in dmraid?? If not, I guess I'll forward the discussion to the dmraid maintainer over at RedHat and see what he has to say as well. Thanks. All of this discussion is prompted by 2 recent supposed disk 'failures' in dmraid setups where one disk will be pristine, but the other will have hundreds of simply corrected errors that have never been fixed over the life of the array, that after disabling the array and running e2fsck are fully correctable. In all the dmraid documentation I have read, I have never seen a warning or note that says: "Periodic disabling of the dmraid array will be required to allow fsck or other disk maintenance processes to be run on the individual disks of the array because enabling dmraid in the BIOS prevents disk maintenance on individual disks in the array." I'm concerned that something like that is needed. The question is, "Is that true?" -- David C. Rankin, J.D.,P.E. Rankin Law Firm, PLLC 510 Ochiltree Street Nacogdoches, Texas 75961 Telephone: (936) 715-9333 Facsimile: (936) 715-9339 www.rankinlawfirm.com -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org