On Maw, 2004-08-31 at 14:54, Rogier Wolff wrote:

So, can we agree on: 
	- might be needed for 
		- Floppies?
		- MO drives
		- older drives

Other random stuff it saves our backside on we don't know about.

How about we set the num-retries to 1, and increase to 8 for
"weird devices" (floppy, MO), and older drives. 

Disagree. I want it robust. If you want to set low retry counts then
the user should do so for special cases like forensics.

I do want to make the num_retries thing a configurable parameter,
should the autodetect get it wrong: We get drives that we want to
recover without the kernel-level retries...

Making it configurable is good, but I can't help feeling that this
belongs at the block layer - I wonder what Jens thinks, it might well
have to be done by the driver because only the driver knows enough but
the ioctl/config option ought to be common.

(still: I argue that you need to consider a "retry-works" error as an
early warning that your media is going bad, and you need to get your
data off ASAP! If the kernel silently retries and succeeds, the user
won't notice a thing and continue using the drive (or MO media) until
the error becomes irrecoverable. I recommend we put the retry at the
user level. As in "person behind keyboard".)

M/O media retries generally do the right thing and have the right
effect. If you want to know if your drive is failing use SMART and ask
the drive

Remember: Storage appliance not disk. Treat it like a storage
appliance and you'll get better results.

Alan