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Re: [Nbd] deadlock in nbd?

Peter Daum wrote:
Mike Snitzer <snitzer@...17...> wrote: > Which IO scheduler are you using? Please have a look at this redhat
bug; turns out that there is definitely an issue with cfq (not exclussive to redhat): https://bugzilla.redhat.com/show_bug.cgi?id=241540
But if you're seeing this on stock kernel.org I'd imagine your just using anticipatory.

... I'll do some more thorough testing to be sure that this was indeed all of it,
but at first sight it looks like this is also what is striking me - On all machines
but one (accidentally also the only one without interface bonding) I had "cfq"
as the default IO scheduler. After settting the scheduler for /deb/nbd0 to "noop",
so far it is running without a problem ...

Ha ha! It works! Thanks a lot for the pointer. For future reference to other people who may not want to go on a search, the secret password is:

echo noop > /sys/block/nbdX/queue/scheduler (replace X as necessary).

I have only one further question: Is it safe to change the scheduler while the device is mounted? I'd like to put that command in my rc.local, but it will only run after the device is mounted.



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