David Rischmiller wrote:
> Firstly I know nothing about Confluence, but have some experience of
> running virtual infrastructures based on VMware.
>
> That difference in performance suggest to me that you are somehow not
> comparing like with like. The difference between physical and virtual
> performance obviously depends on the resource requirements of the
> principal application involved on the server. If these are being
> adequately provided (CPU, RAM, I/O and Network bandwidth) then any
> performance degradation should be very small; definitely not 60:1
> degradation.
>
> There is, no doubt, scope for pathological applications that go against
> all expectations but I think that results in a question mark over the
> quality of the application and it's unlikely to be the situation here.
Thanks for your response.
Also heard from Steve Daniels @ Edge Hill:
> We run Confluence on a VMWare hosted virtual machine and recently had
> some performance issues which sparked a discussion between myself and
> the manager of Core Services. He recalled reading somewhere that if
> Tomcat can see it has 4 virtual cores it waits for all 4 "cores" to be
> available before using them all at once. On a dedicated system this is
> fine, but when those 4 cores/threads are actually spread over numerous
> dual core processors, which also have about 15-20 odd other virtual
> machines running on them the delay can give some performance issues.
>
> We already had the virtual machine's RAM as real dedicated RAM not
> virtual. Now we've gone from 4 virtual cores down to 2, but double
> their processing speed. Starting confluence up went down from a
> similar 7 minutes or so to a much shorter time.
>
We're following this up.
Paul
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