Hyper-V for hospital information system, calculation and requirements?

Question

Hi All,
This is my first post here, i am a technical support and developer for one of hospital information system, because its application for healthcare so this application demands performance, reliability and high availability, after a long discussion with my
team, we decided to deploy our application and database on Hyper-V VM's. But the problem is we never deploy this apps in VM's before, we usually deploy on physical server, here are our scenario:
for VM1 : Application server (Windows Server 2012 R2), our application would be optimal serve 100 users running on 1 processor with 6 cores  (if deploy on physical server) and 16GB memory.
for VM2 : Database server (SQL Server 2012 R2), usually we use 4 to 6 cores (if deploy on physical server) with 16GB memory.
the questions:
1. Can someone help me with the Hyper-V VM's calculation or configuration regarding computing power for host and guest? like how much vCPU? Dinamyc Memory? (we intended using Hyper-V Server 2012 R2 as hypervisor)
2. What if i want to use fail-over cluster ? does our fail-over must be on VM's too?
3. For SQL Server on VM, which one more impact on performance, assign a lot of vCPU or memory?
4. Can someone suggest me the hardware requirements for those scenarios?
Thank you for the help.
Regards,
Mahdi.

Answer 1

Without knowing the exact performance characteristics of the applications, it is really difficult to provide any information about the effects of oversubscribing the CPUs or memory.  So, just look at it as though it were a physical deployment.
"1. Can someone help me with the Hyper-V VM's calculation or configuration regarding computing power for host and guest? like how much vCPU? Dinamyc Memory? (we intended using Hyper-V Server 2012 R2 as hypervisor)"
Many servers you purchase today will come with two processors and 8 cores (forget about simultaneous multithreading at this point) giving you a total of 16 logical CPUs.  Create your VM with 6 virtual CPUs and 16 GB of memory for Application 1. 
Configure your SQL VM similarly.  I don't know what issues might arise with Application 1 with dynamic memory, but SQL performs best without it.  Most servers today will have at least 64 GB of memory.  With the above configuration, you have
plenty of headroom on a pretty average server.
"2. What if i want to use fail-over cluster ? does our fail-over must be on VM's too?" 
With Failover Clusters, you cluster the Hyper-V role.  This means that the VMs will fail back and forth.  Remember, though, this is at the VM level and not at the application level, meaning that if Hyper-V host 1 fails, the VMs restart on Hyper-V
host 2.  Now, it is possible to also create failover clusters between VMs.  This is quite common with SQL.  When clustering VMs, you would need to install VMs on each node of the Hyper-V cluster.  Then if Hyper-V host 1 fails, there is
an instance of SQL running on host 2 ready to take over.  The recovery time is much shorter.  You will have to ask the vendor of Application 1 if it is a cluster-aware application.
"3. For SQL Server on VM, which one more impact on performance, assign a lot of vCPU or memory?"
Without more information, that is pretty hard to answer.  Generally memory helps first, but depending on the types of query/update activity, multiple CPUs is also helpful.  Start at 4 and monitor to see if more would help.
.:|:.:|:. tim