[Ocfs2-users] esx elevator=noop

[Herbert van den Bergh]

I would assume that all bets are off if you're running a cluster inside 
a vm.  There are no garantees for either I/O or cpu scheduling.

Thanks,
Herbert.


On 01/15/2010 10:50 AM, Sunil Mushran wrote:
> The deadline recommendation was for early el4 kernels that had a bug
> in cfq. That bug was fixed years ago.
>
> I am unsure how using noop in guest will trigger starvation. Not that
> I am recommending it. I have not thought about this much.
>
> On Jan 15, 2010, at 9:55 AM, Brian Kroth<bpkroth at gmail.com>  wrote:
>
>    
>> http://lonesysadmin.net/2008/02/21/elevatornoop/
>>
>> I ran across this recently which describes, when operating in a
>> virtual
>> environment with shared storage, how to try and let the storage and
>> hypervisor deal with arranging disk write operations in a more
>> globally
>> optimal way rather than having all the guests try to do it and muck it
>> up.
>>
>> However, this is contrary to ocfs2 recommendation of using the
>> deadline
>> elevator.
>>
>> I'm just wondering if you have any comments one way or the other?
>>
>> My concern would be that while noop might make things globally optimal
>> it would still allow starvation in a single guest which might lead to
>> ocfs2 fencing.
>>
>> Thanks,
>> Brian
>>
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