Extreme console latency during disk IO (8.0-RC1, previous releases also affected according to others)

[Ivan Voras]

Ivan Voras wrote:

> Another data point - the OS in the VM in question hanged today sometime 
> after 5 AM in the following way:
> 
>     * console nonresponsive (also to ctrl-alt-del)
>     * ssh login nonresponsive (timeout)
>     * ping works (!)
> 
> Judging by the last seen timestamp, the machine should have been in the 
> process of receiving rsync backups - so IO-bound.

It looks like something really could be fishy in this area, at least 
with VMWare. The same thing happened again, and I have an additional 
data point: I left 'top' running on the console and when I attached the 
VMWare console to the VM, the top was still running ok, but as soon as I 
hit a key on the keyboard, the OS console locked up. All other symptoms 
were as I enumerated above.