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Intelligent storage switches and gateways
While iSCSI gateways are limited to protocol translation, intelligent storage switches and gateways add storage services like virtualization, snapshots, replication and mirroring. In other words, they're very similar to multiprotocol storage arrays, except that they don't have storage attached.
These devices let storage architects aggregate existing storage, add multiprotocol support (including iSCSI), and provide virtualization and storage management under a single management console. NetApp's V-Series gateways are the most prominent product line in this category. V-Series gateways are NetApp storage controllers without storage attached, providing iSCSI, FC and NAS connectivity to a central storage pool. "We front-ended our HDS Fibre Channel SAN with a NetApp [FAS] 980c gateway to add both iSCSI and NAS capabilities to our SAN," says Baylor College's Layton.
Sanrad's iSCSI V-Switch connects to a blend of SCSI, FC and iSCSI arrays on the back end, and provides iSCSI connectivity to servers on the front end. Similar to the NetApp V-Series gateway, the V-Switch storage service platform supports volume virtualization, provisioning, mirroring, snapshots and replication. "The Sanrad V-Switch not only provides iSCSI connectivity to our Xiotech [Corp.] FC array, it also enables us to manage the FC storage and SCSI-attached SATA storage under a single umbrella," says Spokane Public Schools' Mount.
But this approach may have its drawbacks. "Virtualization in a switch with no storage attached is quite expensive because you have to pay for the switch and you need to get the storage," says Pete Caviness, solution marketing manager at LeftHand Networks Inc.
This was first published in February 2007