27 Februari 2012 7:22
Is it possible to have single edge server in an edge pool?
Can one Edge server/pool serve more than one FE pools?
can an edge pool be stretched across two datacentres, to have one edge server in each datacenter?
What is the best site resiliency solution if MAN is not an option?
any help would be appreciated
27 Februari 2012 10:39
1. Yes , you can have single edge server in a pool.
2. Yes, single edge pool can serve multiple FE pool/Central sites.
3. Streched edge is not a tested topology. As per my understanding it is not supported.
4. Additional edge pool and weight SRV record , http://infrastructurehelp.wordpress.com/2010/11/02/lync-server-2010-and-site-resiliency-for-edge-services/
27 Februari 2012 19:22
Thanks for your reply.
This is my scenario:
All users are hosted on site 1. Currently there is no voice in the enviornment, but could be added later. So services are, IM/web conferncing / external access/ public IC
Site 2 is for site resiliency, in case site 1 goes down, they still want IM to work, so we have site 2. They cannot have a MAN because their existing SQL cluster is not stretched across the datacenters and they cannot change that. So they are requesting another solution.
3 legged DMZ network:
Internet - DMZ - Internal
Internet - HLB - Edge server - FE Pool with 1 FE server / 1 arv/mon/fileshare server
Internet - HLB - Edge server - FE Pool with 1 FE server
So, can both the edge servers be part of one edge pool? for HLBs to work, does each edge server have to be in an edge pool? The HLB also can provide geo resiliency, so if edge1 goes down in site1, can edge2 server all the users in site1?
For multi site, how is the DNS configured? I read the deployment documents but its still not very clear.
29 Februari 2012 10:01
It's not a proposed DR topology.
• Extending VLANs , WAN bandwidth allocation and static routes (Site-2 edge to site-1 internal VLAN) are major challenges in above scenario.
• When you add site-2 edge server on site-1 edge pool , HLB will forward the traffic to Local (Site-1) or remote (Site-2) edge servers based on the load balancing algorithm(least connection or round robin). Remote edge server traffic has to take WAN link back and forth to reach the site-1 pool. So end user experience would be poor when you connected to site-2 edge box. As i mentioned above , this is not a tested topology from MS.
• Site level disaster , both edge servers and pool will goes down in site-1 and your solution wouldn’t give any resiliency to lync services.
Either you can make site-2 as backup registrar (It wouldn’t give IM/Presence resiliency ) or you can force move the users to site-2 and use DMIMPEXP to move user data.
Hope this helps.
29 Februari 2012 11:41
As Saleesh mentioned the best option is have Another site as DR Site.
You would need to plan the DNS (will have to repoint to DR site) and plan backup-restore strategy.
Usually to do a Force move and then restore the backup on the DR site pool.
But this will definately have 3-4 hrs downtime.
01 Maret 2012 1:39
1. An edge pool cannot include both separate Edge Servers that were deployed on two sites. You can refer to the following information:
(The perimeter network need not be stretched between sites.)
2. To get Edge 2 server servers all the users if Edge1 does down, we need to use geographically redundant HLBs and add other DNS records for the Edge Server failover. For more information, I suggest reading the following document. Although it's for OCS, the Lync is also similar to it. You can search and read from “Our test topology used split DNS configuration”.
For details about deployments leveraging HLBs for Lync Server without GSLBs (Global Server Load Balancer), see the Office Communications Server 2007 R2 Site Resiliency white paper:
In addition, the above document also includes the entire DNS configuration.
However, if you try to provide the highest level of load balancing and high availability, a pair of hardware load balancers (HLBs) were deployed with a Global Server Load Balancer (GSLB) at each site. Please refer to the following link:
If you are not very clear about DSN configuration, you can tell us more details about your concerns.
02 Maret 2012 8:06
Thanks for the reply guys.
So, some more info:
The two sites don't have any bandwidth constraints, it is on a separate subnet as it is located in another building.
Also, I've decided not to use HLB but to use DNS failover for Edge. HLB will be used for reverse proxy.
So, as I don't have any bandwidth issue between sites, can I just have one site & two pools?
Then, do I still require two Edge pools? (with one server in each) or One edge pool (with two servers in it)
02 Maret 2012 10:41
Hope you are aware of the limitation of using DNS LB on edge server ; http://technet.microsoft.com/en-us/library/gg398634.aspx.
I would sugest to have a single edge pool with two servers in it. As i mentioned , streching across subnets is not a supported topology.