Pause virtual machine od I/O error

Are you sure? Isn't it possible to check the status of the worker thread using /proc/ filesystem?

I'm no expert in kvm but I don't think that would be reliable. kvm process may be sleeping if guest is not doing anything and AFAIK there is no /proc or /sys interface for kvm that You could check.
 
Tested and after settings rerror and werror it works as expected, I've run badblocks on my virtual machine and disconnected iscsi several times, each time my virtual machine was paused and badblocks did not found any errors.

Is it going to enter stable repository any time soon?
 

Code:
dpkg -L pve-manager | grep "/usr/share/perl5/PVE"
/usr/share/perl5/PVE
/usr/share/perl5/PVE/HTMLForm.pm
/usr/share/perl5/PVE/pvecfg.pm
/usr/share/perl5/PVE/AuthCookieHandler.pm
/usr/share/perl5/PVE/APLInfo.pm
/usr/share/perl5/PVE/ConfigServer.pm
/usr/share/perl5/PVE/HTMLServices.pm
/usr/share/perl5/PVE/SourceFilter.pm
/usr/share/perl5/PVE/URLRewrite.pm
/usr/share/perl5/PVE/Utils.pm
/usr/share/perl5/PVE/I18N.pm
/usr/share/perl5/PVE/Config.pm
/usr/share/perl5/PVE/SafeSyslog.pm
/usr/share/perl5/PVE/Cluster.pm
/usr/share/perl5/PVE/HTMLDropDown.pm
/usr/share/perl5/PVE/HTMLControls.pm
/usr/share/perl5/PVE/Qemu.pm
/usr/share/perl5/PVE/HTMLUtils.pm
/usr/share/perl5/PVE/OpenVZ.pm
/usr/share/perl5/PVE/HTMLTable.pm
/usr/share/perl5/PVE/AtomicFile.pm
/usr/share/perl5/PVE/HTMLGrid.pm

EDIT: My mistake, I'm blind today.