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ERDAS APOLLO & ECW/JP2

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Super Contributor
Posts: 383
Registered: ‎10-12-2015

Feasibility of 2 node cluster with Windows Server NLB

Client currently has a single server running both ERDAS Apollo and GeoMedia WebMap 16.
(I realise preference is to split Apollo and WebMap onto seperate servers)

 

Client would like to add a second server and use Windows Server NLB to load balance the two nodes without introducing a seperate load balance server.

 

 

Looking at the installation guide, appears there is a strong preference for a seperate load balancer and ARR for load balancing.

  • part of install for cluster requires 'load balancer host and port' which is supposed to be seperate from nodes apollo is installed on. With Windows Server NBL my understanding there is no seperate load balancer, so will it still work?
  • Components such as ECW v2, JPIP, Apollo Core Administrator, Geospatial Portal, Apollo Complete WMS work best with client affinity setup. Is it only ECW v2 that absolutely requires client affinity, or would it get by with Windows Server NLB (where I understand affinity is not available).

Has anyone successfuly applied Windows Server NLB to an ERDAS Apollo load balanced scenario?

Or should client seriously consider adding a load balancer running preferably ARR?

Any other feedback/warnings appreciated.

 

thanks

Shaun

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Super Contributor
Posts: 383
Registered: ‎10-12-2015

Re: Feasibility of 2 node cluster with Windows Server NLB

Client believes they can free up an hardware based NetScaler for seperate load balancer.

Any known issues using hardware load balancer (NetScaler)?

Any reason it wouldn't be supported?

 

HardwareNetscalerOption.png

Moderator
Moderator
Posts: 336
Registered: ‎11-16-2015

Re: Feasibility of 2 node cluster with Windows Server NLB

Hi,

 

In theory, you can use any load balancing software you want, but only ARR has been tested with APOLLO by the product center.

Yon can also install the load balancer on the same node than an APOLLO installation. The only thing is that you have to change to change the default port of that node for APOLLO. So, the load balancer will listen to port 80 and redirect the requests to another node or the same node but on another port.

As you mentioned, pay also attention to the services/applications that need client affinity (Geospatial Portal, ECWP v2), you can load balance the others randomly: OGC services (Core, catalogWMS, EAIM, legacy services, catalog requests, etc.).

 

Florent

Super Contributor
Posts: 383
Registered: ‎10-12-2015

Re: Feasibility of 2 node cluster with Windows Server NLB

Thanks Florent - useful info. For hardware or NLB load balancer, my understanding is can deal with Geospatial Portal state by using 'Microsoft's ASP.NET State Service'. That leaves ecwp v2 affinity - will put my thinking cap on.

Staff
Posts: 8
Registered: ‎03-08-2017

Re: Feasibility of 2 node cluster with Windows Server NLB

I have set up an Apollo cluster with NLB.  There shouldn't be a need to worry about the session state.  After the initial request where the target node is determined, each subsequent requests from the same client are routed to the same server node.  I.e.  the node balancing is done per session, not per request.

Super Contributor
Posts: 383
Registered: ‎10-12-2015

Re: Feasibility of 2 node cluster with Windows Server NLB

Thanks Egon - useful info. I had been under the mistaken impression Windows Server NLB didn't support client affinity.

 

Just found out that clients netscaler hardware load balancer supports 'stickability' which seems to equate to ARR client afinity so all should be good.

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