Welcome once again to Implementing Microsoft Windows Always
On VPN, and in this module we're going to talk about high
availability. Up until now,
our infrastructure consists of a single VPN server and a
single NPS server, and while fully functional,
it obviously has some single points of failure. In the event that an
NPS server or a VPN server is offline for any reason,
whether that's a planned outage to apply system updates or an
unplanned outage because of some sort of failure,
the entire solution becomes unavailable and will incur a service outage.
So to eliminate single points of failure, we'll add VPN
and NPS servers to provide redundancy.
This ensures that any time a single server is unavailable for any reason,
either that a planned outage or an unplanned outage,
the service remains viable and users will still be able to
access on‑premises resources remotely.
In addition to redundancy,
administrators may also deploy additional VPN servers, NPS
servers, or commonly both, to provide enough capacity to
meet expected requirements.
A virtual machine provisioned with 4 CPU cores and 8 GB of RAM will usually
support in the neighborhood of about 1,500 concurrent sessions.
Your mileage may vary of course,
but that's a good starting point or a good estimate.
If you plan to, say, support 10,000 concurrent sessions, then you're clearly
going to need additional capacity to meet those needs.
So, in this module, we'll explore the process of adding additional NPS
servers and VPN servers to provide high availability, redundancy, and to meet capacity requirements for our larger deployments.