Jon Hardcastle wrote:

Well, I finished running my none-destructive badblocks check and ran several smart --long tests I also did a forcefsk on the bad boy and NOW the active md4 (with a DEACTIVE vg on it) returns 0 mismatch_cnt. I haven't rebooted it in days though so I just dont know what casued this. No errors in the log, the pending/reallocated sector count is still 0 on all drives.

I have reactivated my VG and am running it again now it is just bizzare.
  

Very interesting!

I'm wondering what we can infer...
I'm thinking probably it was either a fault of the disks, fixed with 
smart --long tests, or a fault of the filesystem, fixed with forced fsck.
What do you think?

Tell us if mismatches start to happen again

Thank you