Re: end to end error recovery musings

Ric Wheeler wrote:

We still have the following challenges:

   (1) read-ahead often means that we will  retry every bad sector at least twice from the file system level. The first time, the fs read ahead request triggers a speculative read that includes the bad sector (triggering the error handling mechanisms) right before the real application triggers a read does the same thing.  Not sure what the answer is here since read-ahead is obviously a huge win in the normal case.

Probably the only sane thing to do is to remember the bad sectors and avoid attempting reading them; that would mean marking "automatic" versus "explicitly requested" requests to determine whether or not to filter them against a list of discovered bad blocks.

	-hpa