7.7 iSNS Servers

For larger IP SAN installations, one or more iSNS management servers can provide centralized discovery, zoning, and security services. Analogous to DNS servers, iSNS servers reside somewhere within the IP network and are accessible through a well-known address.

As shown in Figure 7-8, centralized administration of iSCSI and iFCP storage assets may be provided by an iSNS server whose policies and discovery domain assignments are managed by a management workstation. In this example, three discovery domains have been created to zone assets apart. Discovery domain A includes an iSCSI host and iSCSI storage target. Discovery domain B includes an iSCSI host as well as a Fibre Channel host and Fibre Channel storage connected by iFCP gateways. Discovery domain C includes all iSCSI and iFCP-attached hosts and an iSCSI-attached tape subsystem. Consequently, servers in discovery domains A and B can see only their assigned storage targets but can share the tape library in common.

Figure 7-8. Centralized IP SAN administration via an iSNS server

In addition, through centralized administration of security keys by the iSNS server, storage conversations between zoned initiators and targets can be authenticated and, if necessary, encrypted. Centralized iSNS management servers can be provided in stand-alone products or can be integrated into more comprehensive storage management platforms.