IS Operations and Business Resilience

A SAN presents block-level storage to servers over a dedicated high-speed network (e.g., Fibre Channel or iSCSI), while NAS is a file server that shares file-level storage over the regular LAN using protocols such as NFS or SMB.

Software that creates and runs virtual machines by abstracting physical hardware; Type 1 runs directly on the hardware (bare metal), Type 2 runs on top of a host operating system.

Anyone who controls the hypervisor or its management console can start, stop, copy or reconfigure every guest VM, so compromise or misconfiguration affects all hosted systems; access to it must be tightly restricted, logged and hardened.

The uncontrolled growth of virtual machines that are easy to create but not inventoried, patched or decommissioned; it leads to unmanaged, vulnerable systems and license exposure.

Software that sits between applications and the operating system or network to let distributed systems communicate and exchange data, such as message queues, transaction monitors and application servers.

A switch forwards frames between devices within the same network segment using MAC addresses (Layer 2), while a router forwards packets between different networks using IP addresses (Layer 3).