[Sheepdog] [PATCH 2/2] sheep: don't skip notify event

[Liu Yuan]

On 03/31/2012 06:20 PM, MORITA Kazutaka wrote:

> This change means that all notify events (e.g. vdi creation) block
> membership change events.  I think it is not good to block them so
> long time.
> 


No, VDI creation and deletion doesn't block membership change events,
since current two patches allows confchg to be tackled immediately once
it happens.

We do VDI create & delete in a loop during 60 nodes leaving in a cluster
with large set of nodes, and don't see any evidence that confchg is blocked.

I think the previous strategy that allow IO requests block both VDI and
node event is non-sensible, causing both VDI operation and node event to
be delayed as much as more than several minutes. This is definitely
intolerable for users that do VDI operation and Guests requests are
easily failed during such a long internal.

Thanks,
Yuan

> However, as you say, we need to order the shutdown event with
> membership change ones.  Currently, I don't have a better idea, so it
> is okay to me to merge this patch, but, if possible, I'd like to see a
> better fix for it.