SAP HANA system is composed of three main components: the host, the system, and the instance.
A host is the operating environment in which the SAP HANA database runs. The host provides all the
resources and services (CPU, memory, network, and operating system) that the SAP HANA database
requires. The storage for an installation does not have to be on the host. For multiple-host systems, a shared
storage or a storage that is accessible on-demand from all hosts is required.
For more information about the restrictions that apply to host names in SAP systems, see SAP Note 611361 in
An SAP HANA instance (HDB) is the smallest operational unit on a host. It is the set of SAP HANA system
components that are installed on one host. A single-host system contains one instance on the one host. A
multiple-host system contains several instances distributed across the multiple hosts (one per host). Every
system has an instance number, which is a two-digit identifier. Each instance in a multiple-host system must
have the same instance number.
A system is one or more instances with the same number. The term "system" is interchangeable with the term
"SAP HANA database". If a system has more than one instance, they must be dispersed over several hosts as
a multiple-host system. Every system has a unique SAP system ID (SID).