Server 2019 - TCP/IP tweaks and deprecated features

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Treo
Posts: 25
Joined: Sun May 17, 2020 5:04 pm

Mon May 18, 2020 10:28 am

Hi All,

I am testing a StarWind VSAN 8 two node setup for Hyper-V on Windows Datacenter 2019. It's been running quite solid for a couple of weeks now with no issues. I am about to finalize the configuration before going live and I am working through the various optimizations suggested including the windows tweaks in the online help. The online help shows tweaks only up to server 2016, nevertheless I have applied most of these that are supported by my NICs. However, according to Microsoft the TCP Chimney Offload is deprecated from server 2016. Any idea what I should do or should I just leave alone? Are there any tweaks for the VSAN specific to Server 2019
batiati
Posts: 29
Joined: Mon Apr 08, 2019 1:16 pm
Location: Brazil
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Mon May 18, 2020 2:34 pm

Hi,

I faced the same situation, maybe it helps:

https://forums.starwindsoftware.com/vie ... deprecated
yaroslav (staff)
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Posts: 2279
Joined: Mon Nov 18, 2019 11:11 am

Mon May 18, 2020 2:53 pm

batiati,

Thanks for the info one more time :)
Treo
Posts: 25
Joined: Sun May 17, 2020 5:04 pm

Mon May 18, 2020 5:10 pm

batiati wrote:Hi,

I faced the same situation, maybe it helps:

https://forums.starwindsoftware.com/vie ... deprecated

Dear batiati,

Thank you for your reference, I did see your very useful and detailed article already. Just to be clear your suggestion is to either go back to Server 2016 and use TCP Chimney (which according to Microsoft is deprecated even for Server 2016) or use RDMA?

Does anyone know if StarWind has any recommendations for TCP/IP tweaks on Server 2019?
yaroslav (staff)
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Mon May 18, 2020 6:09 pm

Do you mean WS 2019 running on a physical server or inside a VM?
If you run it on top of physical server, try setting up Jumbos (unless you use Broadcom NICs) to 9000. You can use Least Queue Depth MPIO policy. Everything pretty much simple.
For a lab, you can enable iSER (if your NICs are RDMA-capable). Again, iSER is intended for POC and test purposes only. Do not use it for production.
Treo
Posts: 25
Joined: Sun May 17, 2020 5:04 pm

Tue May 19, 2020 12:15 pm

Thank you for the insight Yaroslav,

I am running WS 2019 on a physical machine and so is the VSAN. I am using Broadcom (57800) and running StarWind on the 10G links directly connected between the two nodes (no switch). I don't seem to have problems with jumbo frames (I've been running Hyper-V) and seem to be getting better performance than smaller frames. WS 2019 is running the Automatic Profile on the NICs for StarWind. Apart from the MPIO policy the any other tweaks necessary?

Noted your point on RDMA
batiati
Posts: 29
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Tue May 19, 2020 5:06 pm

Hi Treo,
Treo wrote:Just to be clear your suggestion is to either go back to Server 2016 and use TCP Chimney (which according to Microsoft is deprecated even for Server 2016) or use RDMA??
That's correct, TCP Chimney was deprecated on Windows Server 2016, disabled by default, but you still can enable it.

In my case, I'm running VSAN on outdated bare-meral server, so, it was better to step back to WS2016 with chimney enabled than stay on 2019 without any TCP offloading; It was a optimization choice based on running a stress-test (several iperf simultaneously) and comparing the results with and whithout tcp offloading. For sure it has minimal effect on daily average workload.

If you are running VSAN inside a VM (Hyper-V or vmware), even without a SR-IOV capable NIC, you should achieve acceptable performance with results close to bare-metal without any TCP offloading.

Regards!
yaroslav (staff)
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Wed May 20, 2020 7:35 am

Hi Treo

With Broadcoms, enabling jumbo frames could lead to communication issues in some drivers. Sometimes it does work, however, if you go with another driver version things may go bad.
Not sure if it is still the case.
If it works, just do not touch it. However, if you have any communication issues, I just want you to consider disabling jumbo frames.
Treo
Posts: 25
Joined: Sun May 17, 2020 5:04 pm

Wed May 20, 2020 9:11 am

Hi yaroslav,

Thank you for the heads up. I read in the forum of issues with jumbo frames for Broadcom NICs and I am keeping an eye out for comms issues. I am still testing and will report if anything adverse comes up.
yaroslav (staff)
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Wed May 20, 2020 10:57 am

Treo,

Yes, please, let us know if any assistance is required.
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