I’ve been having some conversations over the last few days around whether or not Hyper-V replica is a supported solution for providing some level of high availability within a Configuration Manager environment and to be honest I still don’t have a straight answer for you but some guidance you can work to.
Personally I have always recommended Hyper-V replica as a good option to provide some resilience in a Configuration Manager infrastructure where as we all (hopefully) know a site server is a single point of failure. If you run at least some of your Configuration Manager servers on Hyper-V (other virtualisation vendors are apparently available) then you potentially have this as an option to create a redundant site server. Lets stick with the most commonly used and simple example of a single Primary site.
In theory we can create a primary site server with SQL installed and replica that so in the case of a hardware failure you can ‘failover’ to your replica with little downtime. This is generally considered to be an acceptable amount of downtime as after all Configuration IS NOT a mission critical system, this however is a separate discussion altogether. Sounds great right? A Microsoft product running atop another Microsoft product, both products still within their support period, that’s a supported scenario right? Well you would be forgiven for thinking so but it seems that this is potentially not the case.
A colleague recently linked me to this TechNet blog article by George Bethanis who at last check was a Microsoft Support Engineer. It’s a little old now but there doesn’t seem to be anything more recent out there hence the curiosity around this.
You can see he starts the article quite clearly with a statement that Hyper-V Replica is not supported. No confusing that comment.
However, I have discussed this in open forums before and it is clear that people recommend this, use this and it clearly works well for them. I have tried to seek clarification from MVPs and community contributors on this one and like many things I have come across it seems to come down to whether or not the product group have fully tested the combined technologies. Understandably the product are not going to commit to something without full testing it, if they haven’t done that then in theory it’s out of support. That doesn’t mean it doesn’t work and indeed work well in some scenarios. From my conversation on the SMS Architects list (cc @RobMVP) I was particularly interested in a response from someone who works for a large US based communications and media company who says they use it and it was agreed to be supported by their Microsoft Premier Field Engineer and Technical Account Manager. More importantly it works well for them. I’ve discussed this at a WMUG user group meeting a year or so ago and I believe a well known now ex-MS guy was in that meeting and no-one flinched about this.
A general recommendation then if you want to use this would be to only use it if SQL is installed locally with the Primary Site server. Configuration Manager doesn’t support SQL mirroring as (I understand) it cannot absolutely guarantee the content of the database is exactly the same as the original. This seems to make sense also when applied to replica if the SQL is remote as there is an element of downtime when failing to the replica server, if the PSS for want of a better term is ‘out of sync’ with the SQL DB then you could have problems. These are just my thoughts and it’s entirely possible that despite my exaggerated domain name some else knows better. If that is you, drop a comment below!
I was recently sent a link to this recent TechNet forum thread which discusses this issue. There are a few well-educated ConfigMgr folk commenting on this so also worth a read. http://social.technet.microsoft.com/Forums/en-US/c45d66c1-c7c4-4cb2-b18b-d0c256044a09/general-feedback-on-sccm-2012-with-remote-sql-2012-and-hyperv-replica?forum=configmanagergeneral