Re: RAIDframe and bad blocks

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> wd1 has bad blocks and is marked failed. I replace it and reconstruct
> the RAID with a new disk. But wd0 also has bad blocks, and RAIDframe 
> will give up reconstruction because of the read failure.
My ideas/whishlist in this area:

-- Teach RAIDframe about TRIM so it knows which stripes contain data.

-- Optionally pass the name of a new location of the old failed component 
   to the rebuild command, so it can read data from there if reconstruction 
   would otherwise fail.

-- Add a consolidation command that checks and re-writes parity not only if 
   it doesn't match, but also re-write data/parity if it can't be redundantly 
   read. Would need logging and probably rate limiting.

-- On a read failure (ideally if it's known to be a one-block-only problem, 
   but I guess that information is not available at this level), don't fail 
   the component, but reconstruct the block, count and log. Will also need 
   rate limiting.

Of course that's all rather tricky and involved.

What I currently do is, once a week, scan the RAID's components for read 
errors.