Hyperconverged infrastructure (HCI) is software that joins a group of ordinary servers into one system that does the computing, the storage and the virtualisation together. It replaces two things that a data centre usually buys separately: the hypervisor on the servers, and a shared storage array. HCI is sold as software, or as servers with the software already installed.
What does it replace? A traditional data centre has three tiers. Servers do the computing. A storage array, a dedicated system full of disks, holds the data for all of the servers. A storage network connects the two. Each tier is often bought from a different company and managed by a different team. The servers run a hypervisor, which splits each one into virtual machines, and the virtual machines' disks live on the shared array.
HCI removes the separate array. Each server, called a node, has its own disks inside it. The HCI software joins the disks of all the nodes into one shared pool. When a virtual machine writes data, the software keeps two or three copies of it on different nodes. So if one node fails, its data still exists on the other nodes, and its virtual machines can restart there. This is redundancy built into the software. To grow, the company adds another node, and its computing and storage grow together. One management screen runs it all.
Imagine a co-operative bank in Rajkot with 60 branches. Its old setup had 8 servers, a storage array bought seven years ago, and a storage network between them, from three different suppliers. The array is near the end of its support period. The bank replaces all three tiers with 4 HCI nodes, which fit in a quarter of the rack space. Its 120 virtual machines, including the branch banking software and email, move onto the nodes over a few weekends. Six months later, one node's motherboard fails at 11 a.m. on a working day. The software restarts that node's 30 virtual machines on the other three nodes within a few minutes, from the second copy of their data. The branches see a short delay. The supplier replaces the board the next day, and the software copies the data back.
HCI suits small and mid-sized data centres, branch offices and remote sites, where one small team runs everything. Very large data centres often still buy separate enterprise storage systems, because they can then add storage without adding computing.
HCI sellers also run containers on the same nodes, through a Kubernetes platform. The copies that HCI keeps protect against a failed node, but they are not backups. If data is deleted by mistake or encrypted by an attacker, every copy changes too. So the bank still needs backup and recovery software for its servers, and SaaS and endpoint backup for its email and laptops.
Since Broadcom bought VMware in 2023, HCI has been one of the main choices for companies replacing VMware's hypervisor.