Sun Microsystems Virtual Tape Library manual VTL high‐availability option, Server node failover

Key VTL features and options

controls NDMP agent software on the filer (D below). This agent software copies data from the filer over the SAN to virtual tape volumes (E) mounted by the backup media server (F), so no softwre has to be hosted on the VTL appliance.

SAN fabric

Data-mover software on NAS filer copies data over SAN to virtual tapes.

	F		E
media server	VTL appliance			NAS filer
		virtual	physical
		tape
			tape
		library
			library

Ethernet LAN

D

VTL high‐availability option

In a VTL high‐availability system, intelligent self‐monitoring software, redundant hardware, and high‐availability LAN and SAN configurations protect both the data path and your ability to manage storage. To help you to better understand the steps in the failover configuration process, this section provides a high‐level description of the three key components of the high‐availability VTL solution:

■“Server node failover” on page 9

■“Management path failover” on page 10

■“Storage path failover” on page 11.

Server node failover

The Sun StorageTek VTL high availability option uses two server nodes, each configured to monitor its companion. Each member of the pair serves as the primary server for its own storage clients and as the secondary, standby server for those of its companion. To protect against server failures, each server sends heartbeat information to its secondary using a service IP address. If heartbeat information indicates a fatal error in a companion server’s processes, the healthy server notifies its companion that it is assuming primary server responsibility for both sets of clients and initiates failover. If the heartbeat information stops altogether, the healthy server immediately initiates failover. Finally, if a primary server’s own, self‐ monitoring routines detect a storage device connectivity failure and cannot determine if the failure is local, the primary reports the failure to its companion via the heartbeat signal. If the companion, secondary server can access all devices,

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