Add NLB and its operation mode

Question

Hi,

i have Sharepoint server in production. now going to add NLB cluster, just want to know is there any downtime required to adding cluster. i m going to add my production server as a  first host. 

secondly what should be cluster operation mode unicast/Multicast.

My web server on Hyper V

i am referring 2 link one is saying unicast and one is saying multicast so pls guide me. i have 1 NIC on both server. 

http://blogs.technet.com/b/praveenh/archive/2010/12/17/setting-up-load-balancing-on-a-sharepoint-farm-running-on-windows-server-2008.aspx  [Multicast]

http://www.jppinto.com/2009/05/install-and-configure-wlbs-nlb-on-windows-server-2008/ [Unicast]

if something goes wrong will it effect my running / production environment.

Pls suggest.

thx

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iffi

Answer 1

Downtime required for configuring NLB is quite short (about 5 mins) but if it is production I suggest to take it down for 1h or more if environment is more complex. NLB requires also changes in AAM, DNS and some testing:)

Unicast vs Multicast - your second link provides a good explanation. In my experience I preffer to use Multicast mode(but if it will not works you can change it to other mode).

Regards,

Marcin

Answer 2

If your web servers only have one NIC, you should definitely use Multicast mode, as Unicast mode does not function well with a single NIC and can cause port flooding on your switches. I tend to recommend Multicast over Unicast, but you should also confirm that your networking hardware can support Multicast mode (most modern switches can now, but if they can't you're stuck with Unicast).

Also, when you say that you have 1 NIC on each server, are you referring to the VMs or the Hyper-V host(s)? You may want to do some research on the best way to configure NLB on virtual servers, you may need to do some specific config on your Hyper-V host(s) and the VMs to properly get things set up. There's a good document available from VMware that you may want to take a look at for more information: http://www.vmware.com/files/pdf/implmenting_ms_network_load_balancing.pdf.

John

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MCITP and MCTS: SharePoint, Virtualization, Project Server 2007
My books on Amazon: The SharePoint 2010 Disaster Recovery Guide and The SharePoint 2007 Disaster Recovery Guide.
My blog: My Central Admin.

Answer 3

Hi,

thanks for suggestions. i m using Hyper-V. i have discuss with network team they are saying use Unicast.

spq : NLB requires also changes in AAM, DNS and some testing. would you please what changes required at AAM. I know at DNS level i have to map NLB Cluster name and IP. is there any further changes required. pls guide.

thx.

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iffi

Answer 4

Hi,

When a web application is created in SharePoint 2010, you can specify the Public URL for the web app.  To do network load balancing(NLB), you usually create the web app with a host header that is mapped to the NLB virtual IP that all the servers in the NLB cluster share. Make sure that there is a corresponding record for it in DNS.  When the web application is created, the Public URL is what appears as the default zone of the web app.  Seriously.  The other zones can be used for several other good reasons, but the default zone is actually propagated from the load balanced URL field.

By default, a web application will use the server's machine name and port number as the address for a web application. That isn't load balancing, because the address maps to only one machine.  If you are going to do NLB, use a host header for NLB as the load balanced URL for the web app.  When it is created, the web app will propagate to the other SharePoint servers in the farm (be sure to IISRESET /noforce on the servers).

For more information about using NLB in SharePoint 2010, check out the following article:

http://ybbest.wordpress.com/2011/05/30/using-network-load-balancing-to-distribute-load-for-sharepoint2010-%E2%80%93-part3-of-building-my-own-development-sharepoint2010-farm/

Thanks,

Rock Wang

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Rock Wang TechNet Community Support