[Libguestfs] [Qemu-devel] How to emulate block I/O timeout on qemu side?

Richard W.M. Jones rjones at redhat.com
Tue Nov 6 09:43:06 UTC 2018

On Tue, Nov 06, 2018 at 09:14:57AM +0000, Richard W.M. Jones wrote:
> This link shows how to combine delay and error filters together:
>   https://rwmj.wordpress.com/2018/11/04/nbd-graphical-viewer/

Oops, that's in a forthcoming blog post not this one.  Not enough
caffeine this morning.

Combining the filters is easy however:

  nbdkit --filter=error --filter=delay \
         memory size=$size \
         rdelay=$delay wdelay=$delay \
         error-rate=100% error-file=/tmp/error

Then touching /tmp/error will inject errors, and removing /tmp/error
will stop injecting errors.

The documentation says you should be able to write error-rate=1
instead of error-rate=100%, but in fact that was broken until
recently, and fixed in:



Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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