| 1 |
Alan McKinnon wrote: |
| 2 |
> On Monday 24 March 2008, Enrico Weigelt wrote: |
| 3 |
> |
| 4 |
>> does anyone know an (virtual) block device which can do automatic |
| 5 |
>> defect management (if the underlying disks have badblocks) ? |
| 6 |
>> |
| 7 |
>> My idea goes like this: |
| 8 |
>> * one or more devices are assigned to one block device |
| 9 |
>> * a bunch of spare blocks are reserved for defect management |
| 10 |
>> (so the device looks smaller than the sum of assigned disks) |
| 11 |
>> * if an badblock is detected, it's automatically remapped |
| 12 |
>> to an spare block |
| 13 |
>> |
| 14 |
>> In fact, just what drive-internal defect manangement does, but |
| 15 |
>> at OS / driver level. |
| 16 |
>> |
| 17 |
> |
| 18 |
> I don't see the point, unless you are dealing with drives that do not |
| 19 |
> have defect management. |
| 20 |
> |
| 21 |
> What makes you think you can accomplish this result better than the |
| 22 |
> firmware on the drive? It seems to me that if the drive firmware missed |
| 23 |
> the opportunity to relocate the bad block, then your window of |
| 24 |
> opportunity to do it in your code has long since passed. IOW, the OS |
| 25 |
> code cannot possibly ever achieve it's design result. |
| 26 |
> |
| 27 |
> Just a thought, maybe you know some aspect of disks that I don't and can |
| 28 |
> see where this would be useful. From where I sit, I can;t see any such |
| 29 |
> use-case. |
| 30 |
> |
| 31 |
> |
| 32 |
|
| 33 |
While I see what Alan is saying, I'm pretty sure LVM does it. Device |
| 34 |
Drivers -> Multiple Devices Driver Support -> Bad Block Relocation |
| 35 |
Device Target. I've never played with it but I assume there's a lot of |
| 36 |
good reading on it. |
| 37 |
|
| 38 |
-- |
| 39 |
HTH, Eric |
| 40 |
-- |
| 41 |
gentoo-user@l.g.o mailing list |
Archives