Can hardware and Elastix as a server with the roles of a router, virtualbox on RAID + VLM

Question

virtual box

Good day!
I am not familiar with linux, I wanted to ask people who know how real the task is, what problems may arise. To what extent is such a "solution" fault-tolerant.
The task is the following, to organize a server that would perform the functions of:
-router
-IP PBX
-Virtual machine W2008R2
-File server with RAID
There is actually no budget, there is a desktop c
-CPU i5 of the previous generation
-2min HDD 5600rpm 500Gb on which I plan to build software (mdadm ) RAID 1 + LVM
-1n HDD 1Tb 7200rpm for backups
-12Gb RAM
-2a 1000TX interface I
plan on it:
- how to install elastix host OS to organize nat with proxying
- using VirtualBox to run W2008R2 c not very demanding special. Software + MSSQL 2008R2
Questions:
- Is it generally viable or already a perversion?
- Whether there will be enough productivity, in a network a maximum of clients 10-15. Applications are lightly loaded on W2008R2.
- What will happen to the VHD drive W2008R2 if the power is turned off at the machine. (BBP is available, very powerful, but still)
- How about USB forwarding in VirtualBox on CentOS?
- How does software RAID 1 behave, can the OS fail to boot if the power is suddenly turned off again?
Perhaps you can offer an alternative option based on the conditions?

Answer 1

I will answer myself. It's better to use proxmox. Will cope if there are not many customers.