Site failover design


  • Hi,

    Were putting together a new design for both HA and DR (site failover). Im hoping to get some pointers, ideas, opinions etc. We will be utilizing a hyper-v cluster, running on server 2016. We will most likely get two sets of SANs and utilize storage level replication. First of all, should we consider Storage Spaces Direct (instead of a SAN) considering the datacenter licensing cost?

    My question is, looking at the simple DR diagram below, what solution(s) exists that would provide me with the most efficient and least down-time failover experience?  That challenge im seeing is that the storage device in the secondary site is naturally going to be on a different IP subent. This means that even if i add the nodes in the secondary site to the existing cluster (so all nodes across all sites are aware of just one cluster), i would need to add the Luns on the secondary storage to the cluster (when a disaster strikes) and/or create a new CSV, and then reconnect the nodes to it and boot he VMs? Is this the ideal method?


    luni, 11 iunie 2018 22:56

Toate mesajele

  • "Should we consider Storage Spaces Direct (instead of a SAN) considering the datacenter licensing cost?"

    Yes, you should consider it.  It is very possible that the cost of your two SANs may equal the cost of the Datacenter licensing.  Besides, if the reason you are creating a highly available cluster is to run VMs, you would most likely be better served by purchasing Datacenter licenses for the hosts anyway.

    "Is this the ideal method?"

    It is not likely that you will get an answer for the 'ideal' method from a forum.  The 'ideal' requires significant work on understanding your business and technical needs.  That is more information than is possible to effectively communicate in a forum.

    That said, I will try to address some issues.

    I don't understand why you state "the storage device in the secondary site is naturally going to be on a different IP subnet."  There is no requirement for that.  Stretching subnets between sites is something that has been done for years.  There are reasons not to do that, but it is possible, so there is nothing to assume that to be 'natural'.  It may be a requirement of the SAN replication technology from the SAN vendor, but I am not certain that it is a requirement if you use Microsoft's storage replication.

    From a simplicity standpoint, it might be simpler to create one cluster in each site and use Hyper-V replication between the sites.  It is possible to replicate with either the same IP configuration for both sites, or you can configure alternate IP for the DR site.

    If you do want to consider S2D, you will not be able to stretch the cluster between the sites (yet), but Storage Replication or Hyper-V Replication is available.


    • Propus ca răspuns de Jin Chen marți, 19 iunie 2018 08:23
    marți, 12 iunie 2018 12:24
  • Hi Tim,

    Thanks so much for the feedback and info. You're right, there no "ideals", i just looking for some ideas. I believe storage replication is also a datacenter feature, right? Hyper-v Replication would not work for us because it keeps a consent open snapshot on the VM. The main issue with that (aside from performance) is the inability to adjust
    the storage vhdx size. The stretch cluster functionality of Storage Replica is precisely what we're looking for, but ill need the datacenter licenses...

    Storage Replica stretch cluster - if i understand it correctly - will replicate a CSV disk. From an accessibility standpoint, its always C:\ClusterStorage\Vol1, regardless of the site/node or underlying disk. In the event of a DR situation, a VM can easily and automatically move from the primary site to the DR site without any additional config. This is absolutely awesome! 

    S2D isn't going to help me because i need a site-to-site failover solutions for hyper-v. Are there any solutions like SR for failover clustering without a datacenter licenses? From a cost standpoint, obtaining storage (with replication functionality) might actually be cheaper for us than a datacenter licenses, because were hosting (IBM/Softlayer) and a datacenter licenses would be a monthly cost. Most of our VMs are Linux...

    Btw, does VM Load Balancing also require a datacenter licenses? 

    joi, 14 iunie 2018 21:11
  • Most SAN vendors have some sort of replication software.  Until Microsoft came out with its own, that was the most common way customers replicated data from one site to another. is a pretty complete list comparing features available in Standard or Datacenter.


    • Propus ca răspuns de Jin Chen marți, 19 iunie 2018 08:23
    vineri, 15 iunie 2018 12:25
  • Hi,

    Just want to confirm the current situations. 

    Please feel free to let us know if you need further assistance.

    Best regards,


    marți, 19 iunie 2018 08:23