HP 3PAR StoreServ Storage Concepts Guide (OS 3.1.2 MU2) (QR482-96384, June 2013)

ATF automatically redirects host I/O from a failed source system to the replicant target system in
a manner that is transparent to the host and causes minimal disruption to service. ATF uses the HP
3PAR Quorum Witness to monitor for HP 3PAR StoreServ array failure and to automatically
determine whether a failover of host service is required. The HP 3PAR Quorum Witness and related
technology provide the automation to trigger the transparent failover technology to execute the
migration of the I/O path.
To optimize service or facilitate maintainence, transparent failover also provides user-initiated
failover of host I/O from one HP 3PAR StoreServ system to its replicant. User-initiated transparent
failover is also known as managed transparent failover (MTF).
ATF and MTF technology are key elements in providing and maintaining a high-availability storage
solution between two sites and are fundamental building blocks in the wider HP 3PAR Peer
Persistence technology set. From a technology perspective, ATF can be seen as a super-set of MTF.
ATF requires some additional configuration beyond that required for MTF.
60 Enhanced Storage Applications