Extended Parallel Server allows multiple storage-manager instances, but only one instance per node. You can configure and use different storage-manager brands for different purposes. For best performance, run onbar-worker processes on all nodes that have storage devices. For example, you have two storage devices, a tape drive and a jukebox, and want to connect them on different nodes. When an onbar-worker is on each node, the data moves faster because it does not have to travel over the network. For complex examples, see Using ON-Bar Configuration Parameters on Extended Parallel Server.
For information on how to update the sm_versions file when using multiple storage managers, see step 4 in To update the storage-manager definition in sm_versions.
Some third-party storage managers have a client/server architecture. For these storage managers, one instance per node means one storage-manager client.