Re: List of mismatched blocks?

[Niobos <niobos@dest-unreach.be>]

On 2010-07-03 23:29, Mario 'BitKoenig' Holbe wrote:
> Niobos <niobos@dest-unreach.be> wrote:
>> Weekly, I'm checking my RAID1 array using:
>> Every few weeks, I get a mismatch count (which are easily solved with a
> 
> Which kernel version and which filesystem on top of the RAID1?

Linux serv02.<omitted> 2.6.31-15-server #50-Ubuntu SMP Tue Nov 10
15:50:36 UTC 2009 x86_64 GNU/Linux

/dev/md1 on / type ext3 (rw,errors=remount-ro)


>> "sync"). Is there an easy way to get a list of blocknumbers that
>> mismatch? I'd like to figure out what may be causing this mismatch.
> 
> You can just cmp -l your component devices and get a list of addresses
> and mismatches - easy to convert to block numbers. For ext2/3 I'd bet
> the mismatches are in inode blocks.
I found out about cmp -l, but that gives me roughly 9 million differing
bytes. They are nicely grouped in ranges, but I was hoping for a way
that would output "sectors 517-523 and 4554-4559" or similar.

For the few mismatches that I calculated manually, the mismatching file
seems to be the ext3-journal itself.

I'm running cmp on an active RAID. My guess is that this cause a large
number of false positives: cmp reading both members at a different time,
and hence reading a different version. That was the main reason to ask
for another way to get the mismatching blocks through the raid-layer.

Niobos

PS: Both disks report "rellocated sector count = 0" via SMART.