mismatch_cnt != 0, member content mismatch, but md says the mirror is good

[Michael ODonnell]

> As I understand it, the explanation in question applies to swap
> partitions only.  (Swap is somewhat unique in that the kernel can
> "know" a given block on disk will never be read again.)

Yah, you're referring to the case where a page that's just been written
out is immediately dirtied again so those freshly written disk data are
abandoned since they're no longer the most recent bits representing
the page in question.  He indicates that he thinks this might also
be possible for memory mapped files but now that I've read it again I
confess I don't understand his follow-up:

> This can conceivably happen with out swap being part of the picture,
> if memory mapped files are used.  However in this case it is less
> likely to remain out-of-sync and dirty file data will be written
> out soon, where as there is no guarantee that dirty anonymous
> pages will be written to swap in any particular hurry, or at any
> particular location.

...so I guess the only thing we know for sure is that these guys know the
problem exists and don't believe it to be dire.  FWIW, as in your case
the MD device this was reported against is not engaged in any swapping.

_______________________________________________
gnhlug-discuss mailing list
gnhlug-discuss at mail.gnhlug.org
http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/