On Thu, Sep 15, 2011 at 3:03 PM, Dan Williams [off-list ref] wrote:

Does it consider the raid5/6 write hole in what it caches?  Guess I
need to take a look at the code, but just wondering if it considers
the need to maintain a consistent strip when writing back to raid5/6
array, or would there still be a need for a separate driver/region of
the SSD for caching that data.

Do you mean - if you're caching a raid5 (not the individual devices,
the entire array) the parity blocks?

In that case no, bcache will never see them. However, if you're doing
writeback caching that won't be a huge problem since you'll end up
with more full stripe writes.