On Thu, Apr 05, 2012 at 06:31:49PM +1000, Russell Coker wrote:
deb http://www.coker.com.au squeeze misc
In the above Debian repository for i386 and amd64 I have a version of mdadm patched to send email when the disks have different content. I am seeing lots of errors from all systems, it seems that the RAID code in the kernel is reporting that 128 sectors (64K) of disk space is wrong for every error (all reported numbers are multiples of 128). Also I suspect that the Squeeze kernel has a bug in regard to this. I'm still tracking it down.
if you are looking at raid1 or raid10, then see 'man md' as mismatches are expected. eg. http://fedorapeople.org/gitweb?p=dledford/public_git/mdadm.git;a=commitdiff;... 64k is prob the dma size the fs or app is using. we extensively investigated mismatches with md raid1 and ext3 (or 2, I forget) a few years ago and the different blocks were indeed always in the unused part of the device - never in the fs. I might even have a reproducer for this somewhere - wasn't too hard to setup as I recall. if not raid1/10 then it's probably real. which kernel is 'squeeze' based on? have you ever seen data damage in the fs due to mismatches? cheers, robin