Re: Problem identified: WAPL/RAIDframe performance problems

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> These disks lie about their actual sector size.
> These disks just follow their specification.

That's as meaningless as...on, to pick an unreasonably extreme example,
a hitman saying "I was just following orders".

> They also report the true sector size.

Not according to the documentation, at least not in the one case I
investigated.  The documentation flat-out says the sector size is 4K,
but the disk claims to have half-K sectors.

The problem is that there are two sizes here, which have historically
been identical: the sector size on the media and the granularity of the
interface.  Trouble is, they were identical for good reason.  I
consider decoupling them slightly broken.  I consider decoupling them
without updating the interface to report both sizes cripplingly broken.

> So should the disk lie about the blocks you can address or lie about
> some recommended block size for accesses?

Neither.  The sector size claimed to the host should equal both the
sector size on the media and the granularity of the interface.

Either that or a new interface should be defined which reports both the
media sector size and the interface grain size.

Anything else is IMO a bug in the drive and should be treated as such,
which in NetBSD's case I would say means a quirk entry, documented as
being a workaround for broken hardware, for it.

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