Re: [PATCH] bcache: make stripe_size configurable and persistent for hardware raid5/6

From: Martin K. Petersen
Date: Mon Jan 10 2022 - 11:14:49 EST



Eric,

> Ok so `git blame` shows that Kent added this to md/raid5.c in
> c78afc6261b (Kent Overstreet 2013-07-11 22:39:53 -0700 7526)

Yep.

> Do you think we should leave the md-specific
> raid_partial_stripes_expensive setting and require users of RAID
> controllers to set the bit themselves in bcache---or---remove all
> raid_partial_stripes_expensive code and always treat writes as
> "expensive" when `opt_io` is defined?

I'd prefer the latter since that was the very intent of exporting the
device topology in an abstract and protocol-independent fashion.
However, I don't know enough about bcache internals to know whether it
is always the right choice, what the trade-offs are, etc.

--
Martin K. Petersen Oracle Linux Engineering