High Availability Cluster with 2 ReadyNas units

Does anyone know how could I set up a failover cluster with two ReadyNAS RN 2120?. I am worried about it because right now my NAS unit represents a single point of failure so is it possible to do it?. If so, how?
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Ludwig DiehlSystems ArchitectAsked:
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Carlos IjalbaSenior SysadminCommented:
Well, if you are running a VMware infraestructure on them, you can use Veeam Backup & Replication to replicate VMs from one NAS to the other, or you can use VMware's own Disaster Recovery Manager (DRM).
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Ludwig DiehlSystems ArchitectAuthor Commented:
Hello. Thanks for your answer. I am using Hyper-V (Windows Datacenter 2012 ). So what I need is to set up one as the active node and the other one as passive. Is this possible to be accomplished?. If yes, how?. I have one NAS unit but thinking to buy the other one so they can be redundant. By the way I was considering to buy a synology RS815RP+ to be the master node or should I stick with the ReadyNAS RN 2120?.
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Carlos IjalbaSenior SysadminCommented:
Hi Ludwig,

In any virtualization environment, what you have is a physical host with the virtualization OS or type 1 hypervisor (VMware ESXi, Hyper-V, PowerVM, Xen, etc) and then you attach some enterprise storage to it (this can be a SAN, a NAS or a VSAN), so then you have a virtualized environment where to create VMs, expand storage, etc.

This is the most basic setup, and not good enough for enterprise setups, what you need is a second hypervisor host, and depending on your storage, a second storage device.

Once you have 2 hosts, they must be able to see both storages, so if one fails, they can move or start VMs on the other storage.

Now, how to implement HA clusters?, well you can setup HA on the hypervisors or of course you can setup a traditional HA cluster in 2 VMs, one in each host/storage device.

In any case is always better to have the same kind of host and storage device in each side to be coherent and save yourself compatibility problems, but you could mix and match if you so desire and don't mind the extra headaches that this option might give you.

In your particular case, I would buy another NAS like the one you have, and then just setup a Hyper-V cluster to protect your VMs.

If you need some more info on storage I have an article that might interest you:
http://www.experts-exchange.com/articles/18712/Storage-101-common-concepts-in-the-IT-enterprise-storage.html
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Ludwig DiehlSystems ArchitectAuthor Commented:
Thank you very much for the answer. However I am still wondering how to do that. Would you mind sending a diagram so I can better understand it?. I have two servers with windows 2012 DataCenter each and planing to buy another storage solution, lets say synology RS815RP+ to act as the master.  I would like to have redundancy on those two servers and the two NAS (where the VM are supposed to be stored).

Thanks in advance
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Ludwig DiehlSystems ArchitectAuthor Commented:
Here someone has almost the same prob I have. Although I need something more reliable.
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Carlos IjalbaSenior SysadminCommented:
High availability clusters in a virtualization environment are done by replicating VMs across different storage pools.

The difference here is that apart from that, VMware has FT or Fault Tolerance, where it does replicate the full execution stack (RAM & CPU) to another machine, so if one goes down, the other carries on in the same spot. Problem is: only VMware vSphere has this functionality, Hyper-V only does VM replication (as far as I know).

However you can setup application or OS traditional HA clusters in 2 VMs, each in a different storage pool. Which would be the way you have to go within your infrastructure.
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Carlos IjalbaSenior SysadminCommented:
In any case, it's good to consider that FT might no be the holy grail to everybody (it has special prerequisites and licences), there is a good article by MS here:

Evaluating High-Availability (HA) vs. Fault Tolerant (FT) Solutions
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Ludwig DiehlSystems ArchitectAuthor Commented:
So what would be your advice if I need some level of FT?. Two physical storages, only one with "full" redundancy?. I am worried about this because I usually see redundancy solutions for VM but not specifically for the storage which indeed is a single point of failure isn't it?
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Carlos IjalbaSenior SysadminCommented:
What I mean is that you have 2 hypervisors, and each can see both NAS devices, then the VMs are located in one NAS, but replicated to the other (therefore they are in both NAS).

If a Hypervisor fails, the other hypervisor powers up the VMs that were up and running in the failed hypervisor.

If one NAS fails, you have all your VMs in the other NAS, and are powered up by the hypervisor.

Basically if you have a server or NAS failure, the incident will be like rebooting your servers.


You can follow the following article here on EE, on how to setup such an environment:

Guide-Creating-a-Hyper-V-Cluster

You also check a detailed tutorial series on how to build a complete hyper-v setup searching in google for "How to Successfully Create a Hyper-V Cluster Using Virtual Machine Manager".


There are NAS solutions with redundant power supplies and redundant controllers, so they are also high available solutions by themselves, but that is reserved for expensive NAS or SAN devices, so it is quite commonplace to have 2 NAS with replication.

As i said before, you can replicate VMs using software like veeam backup.
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Ludwig DiehlSystems ArchitectAuthor Commented:
Thank you for such great explanation!
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Carlos IjalbaSenior SysadminCommented:
No problem Ludwig, I'm glad I could help.
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