KVM guest Buffer I/O errors

[Matej]

Hi,

I have an issue which is very similar to some others that I found 
unsolved, such as:
- https://bugs.launchpad.net/ubuntu/+source/linux/+bug/577785
- http://centos.distrosfaqs.org/centos-virt/guests-pausing-suddenly/
- http://ubuntuforums.org/archive/index.php/t-1450439.html

I have 8 guests installed on an internal RAID and all of them work as 
they should, except one (that is the largest of them and sadly, the most 
important one). There are no drive problems reported in none of the 
other host's logs. The most importantly, there is nothing in the host 
system logs at all, but although it is so, we have replaced both drives 
by new ones just out of the box. But the issue remains so I am pretty 
sure it's now hardware-related, but have no more ideas what to do next. 
I could just create a new guest and transfer the services and data, but 
since this happened without me changing anything (at least 
intentionally), I want to find out a reason why did it actually happen 
and how to prevent it.

Any help or ideas on this matter are very welcome.

Thanks,
Matej