[THIN] Re: Video Performance
- From: Chris Grecsek <chris@xxxxxxxxxxxxxxxxxxxx>
- To: "'thin@xxxxxxxxxxxxx'" <thin@xxxxxxxxxxxxx>
- Date: Tue, 22 Jul 2008 08:53:52 -0700
Our first "test" was the subjective multi-media experience test and we were
surprised to see that the multi-media experience was "the same" on the VM CSG
and on the physical CSG box. At that point we decided to get a bit more
scientific/gather concrete evidence to confirm that result via the performance
counters.
The test was late in the day so there were maybe 70 users on the VM CSG and
yes, we only had the single user on the physical CSG. They physical CSG was a
modern dual proc, dual core box w/4gig or ram so it wasn't a gimped box in any
way. Actually we used the most powerful spare box we could find just to try to
make the physical test box look as good as it could.
-----------------------------
chris grecsek | centered networks | t:415-294-7776 | f:415-294-7772 |
chris@xxxxxxxxxxxxxxxxxxxx<mailto:chris@xxxxxxxxxxxxxxxxxxxx>
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Steve Greenberg
Sent: Monday, July 21, 2008 11:35 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Video Performance
That is good feedback, thanks for coming back and sharing the results. I
wonder, on the physical box, aside from counters, did you subjectively
experience better multi-media performance? You said that the test box only had
one session on it, I have to think it performed better than the VM with 400
users?!?
Steve Greenberg
[cid:image003.jpg@01C8EBD8.77582DB0]Thin Client Computing
34522 N. Scottsdale Rd D8453
Scottsdale, AZ 85266
(602) 432-8649
www.thinclient.net
steveg@xxxxxxxxxxxxxx
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Chris Grecsek
Sent: Monday, July 21, 2008 10:38 PM
To: 'thin@xxxxxxxxxxxxx'
Subject: [THIN] Re: Video Performance
I thought I'd share the results of our testing in comparing video performance
between a VM WI/CSG and a physical WI/CSG. We measured a number of counters
with respect to session latency, bandwidth usage, etc. and it turns out that
our performance/metrics was just about identical on the VM as on the physical
machine. The VM CSG still had a number of active sessions and the physical only
had a single, test session running on it.
We were able to isolate the performance issue to the CSG - we confirmed that
the WI is not part of the degradation.
So, while this was good in that we now have a definitive answer in that no
matter how much available bandwidth we have to help improve video quality, it
won't get any better as long as we're connecting through a CSG. I guess it's
time to get an eval of the Netscaler products.
Thanks!
Chris
-----------------------------
chris grecsek | centered networks | t:415-294-7776 | f:415-294-7772 |
chris@xxxxxxxxxxxxxxxxxxxx<mailto:chris@xxxxxxxxxxxxxxxxxxxx>
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Steve Greenberg
Sent: Friday, July 18, 2008 4:26 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Video Performance
NIC is I/O and in a virtualized environment it has significant overhead in that
a software layer is added to virtualize the NIC in a way that slows it down
quite a bit. I would suggest, in general, that with 400 concurrent connections
you have exceed what a VMWare based CSG can effectively handle, probably by
quite a bit actually. The quick and easy proof is to spin up a CSG on a raw box
and check the different in response times. The overhead in this case is not
going to show in monitored utilization but more in the user experience of
latency on the rich media stuff you are referring to. It is not a matter of
utilization of VMWare resources as much as the fact that the virtualization I/O
translation layer is simply too inefficient. Stay tuned- later this year Intel
promises to have hardware NICS that are virtual machine aware...
The Netscaler is the product I am referring to. If you buy Netscaler Enterprise
it includes a feature called Access Gateway. However, you can also buy the same
product with only the gateway feature and it is called Access Gateway Enteprise
Edition. It is very confusing, but in the end they are the same box with
different software licenses loaded!!
Steve Greenberg
[cid:image003.jpg@01C8EBD8.77582DB0]Thin Client Computing
34522 N. Scottsdale Rd D8453
Scottsdale, AZ 85266
(602) 432-8649
www.thinclient.net
steveg@xxxxxxxxxxxxxx
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Chris Grecsek
Sent: Friday, July 18, 2008 1:50 PM
To: 'thin@xxxxxxxxxxxxx'
Subject: [THIN] Re: Video Performance
Excellent feedback - thanks Steve! When you say VMware is bad with I/O do you
mean disk or NIC or both? The perfmon counters we're running on the VMs show
very little utilization of disk or NIC so I guess we'll just see how it goes.
We do have the WI and CSG on two separate VMs. We have about 400 concurrent
connections on this WI/CSG set.
You also mentioned the Netscaler Access Gateway as a possible upgrade path from
the WI/CSG. I'm doing some research but I must say, Citrix's product naming
bonanza makes me not 100% sure I'm looking at the correct product. I found
information on the Access Gateway Enterprise Edition (AGEE) but is that a
different product than the Netscaler Access Gateway? Was there a specific
feature of the product that you think would be making the difference or is it
just the fact that the device is designed to handle/manage that specific type
of traffic/load?
-----------------------------
chris grecsek | centered networks | t:415-294-7776 | f:415-294-7772 |
chris@xxxxxxxxxxxxxxxxxxxx<mailto:chris@xxxxxxxxxxxxxxxxxxxx>
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Steve Greenberg
Sent: Friday, July 18, 2008 1:07 PM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Video Performance
Now that we know it is running on VMWare that could be the bottleneck right
there- CSG is I/O intensive because of the nature of what it is doing as a
proxy, this is the one area that hypervisor virtualization is still very weak
at....
Steve Greenberg
[cid:image003.jpg@01C8EBD8.77582DB0]Thin Client Computing
34522 N. Scottsdale Rd D8453
Scottsdale, AZ 85266
(602) 432-8649
www.thinclient.net
steveg@xxxxxxxxxxxxxx
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Chris Grecsek
Sent: Friday, July 18, 2008 11:21 AM
To: 'thin@xxxxxxxxxxxxx'
Subject: [THIN] Re: Video Performance
Hi Joe,
Thanks for the speedy response!
We're not using any LBs - there are no network devices other than a standard
PIX.
The WI and CSGs are both VMs on ESX 3.5. Based on your question I think we'll
setup a WI/CSG on a standalone server "just to see" even though we're not
seeing high utilization.
At this point we have not isolated the WI or CSG. We're going to setup an
additional site on the WI that will not use the CSG so that should achieve the
isolation.
We've done quite a bit of testing with the speedscreen/multimedia stuff - I
think we've tried every conceivable combination in the policies and farm
settings . I believe the policies should apply the same whether we come in via
the CSG/WI or the PN.
Image acceleration using lossy compression: enabled; compression
level: do not use lossy compression; speedscreen progressive display:disabled
Speedscreen browser acceleration: off; speedscreen flash: enabled -
all connections; speedscreen multimedia: enabled - buffer = 10.
Thanks again,
Chris
-----------------------------
chris grecsek | centered networks | t:415-294-7776 | f:415-294-7772 |
chris@xxxxxxxxxxxxxxxxxxxx<mailto:chris@xxxxxxxxxxxxxxxxxxxx>
________________________________
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Joe Shonk
Sent: Friday, July 18, 2008 10:35 AM
To: thin@xxxxxxxxxxxxx
Subject: [THIN] Re: Video Performance
It could be a couple of things.... Have you tried removing CSG from the
equation and isolate if its WI or CSG? Is your CSG box running in a Virtual
Machine? Do you have a LB in front of your WI and/or CSG box? How are you
Applying the Ctx Policies for the SpeedScreen/multimedia.
Joe
From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of
Chris Grecsek
Sent: Friday, July 18, 2008 10:24 AM
To: 'thin@xxxxxxxxxxxxx'
Subject: [THIN] Video Performance
We provide published desktops via Citrix/terminal services delivered via the
internet. All users come in through the web interface/CSG via high speed,
burstable (up to 100mb) connections. Most of the branch offices are <50 users
so connectivity/maxxing out the pipe is not an issue. We don't use any
bandwidth restriction policies - users can use as much bandwidth as they'd
like. We have bandwidth monitoring to look at all traffic and have our
firewalls setup so that only Citrix traffic is using the burstable connection.
Latency is sub 20ms and we have no packet loss.
Like everyone else using Citrix we've had challenges with video performance on
the published desktop (Windows media player works great - Flash/other codecs,
not so much). We had an interesting discovery today and I was curious if anyone
could answer why/how this happens...when we connect to a published desktop via
the WI/CSG (from one of our branch offices) video performance is bad. We ran a
test today from within the datacenter where we connected to a published
desktop, locally (from a laptop at the DC), using the Program Neighborhood as
opposed to coming in over the WI/CSG and low and behold, video performance was
excellent.
When we look at the amount of session bandwidth being used it's nearly the same
when coming in via the WI/CSG as it is when testing at the datacenter. So I
guess the question is, is there something with the way the WI/CSG works that
would be restricting/degrading the video performance (we ran performance
counters on the WI/CSG and it doesn't seem to be working very hard), is there a
difference between using the Program Neighborhood verses the web client, etc.?
We're on Citrix 4.5, latest rollups, latest version of the client, etc.
If anyone has any ideas, it would be much appreciated.
Thank you!
Chris
-----------------------------
chris grecsek | centered networks | t:415-294-7776 | f:415-294-7772 |
chris@xxxxxxxxxxxxxxxxxxxx<mailto:chris@xxxxxxxxxxxxxxxxxxxx>
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