Unlike managed VPS plans, unmanaged VPS plans are not actively managed by A2 Hosting. Unmanaged VPS plans are for more advanced users who are comfortable using the command-line interface and doing system administration tasks. These plans include root account access so you can customize the server as much as necessary. As a result, you are responsible for the following items:

A key aspect of VPS internet hosting is its virtualization capabilities. With VPS, the hosting provider divides each physical server into multiple smaller virtual servers with private and dedicated RAM and hard drive space. This provides site owners with a more isolated hosting environment without disruptions from other clients sharing server space.

If you want to customize your Web hosting server or need more technical flexibility than shared hosting, but the price tag of a dedicated server is prohibitive, then a VPS can be a brilliant option. You get full root-level access to install and delete software, set permissions, create accounts and determine your customized server environment – but because you are still sharing hardware you don't have to be concerned about the physical server maintenance and security.
VPS hosting contains the best elements of shared hosting and dedicated hosting services. Like shared hosting, VPS hosting puts your website on a server that also has other sites running on it, except that there are fewer sites per server. The sites share the cost of running on the server, which results in a monthly or yearly charge that's less than the relatively high price tag of dedicated hosting.
Unmetered hosting is generally offered with no limit on the amount of data-transferred on a fixed bandwidth line. Usually, unmetered hosting is offered with 10 Mbit/s, 100 Mbit/s or 1000 Mbit/s (with some as high as 10Gbit/s). This means that the customer is theoretically able to use ~3 TB on 10 Mbit/s or up to ~300 TB on a 1000 Mbit/s line per month, although in practice the values will be significantly less. In a virtual private server, this will be shared bandwidth and a fair usage policy should be involved. Unlimited hosting is also commonly marketed but generally limited by acceptable usage policies and terms of service. Offers of unlimited disk space and bandwidth are always false due to cost, carrier capacities and technological boundaries.[3]