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Which approach is better depends on who'll control what resources after the consolidation. Cisco's FC director architecture assumes companies will want to:
- Consolidate or connect remote SAN islands onto its MDS 9500 Series Multilayer Directors.
- Centralize the administration of user and administrator accounts in the FC SAN.
- Centralize the control and sharing of SAN resources across virtual and remote SANs.
With VSAN functionality a native part of the MDS 9513 SAN-OS, users don't have to buy specific blades or switches to obtain this functionality. Administrators may grow VSANs logically on a port-by-port basis instead of adding a new blade into a 48000 or introducing an FC switch into the fabric as Brocade requires. Using director blades or switches adds the step of moving the physical FC connections of resources (servers, tape drives and storage arrays) to the ports on the director blade or switch.
The MDS 9513 eliminates these steps by allowing admins to configure any MDS 9513 FC port as an "E_Port" and connect it to any vendor's remote SAN switch. VSANs are then created on the MDS 9513, which admins may define to just include the FC ports connected to the remote SAN island. Specific resources among VSANs are shared using Inter-VSAN zones (IVZs).
This is where the issue of control enters. The MDS 9500 Series Multilayer Director supports up to 1,024 VSANs in a single fabric and each VSAN supports the
Preserving SAN autonomy
Brocade's director architecture assumes companies will want to consolidate FC ports and share resources among LSANs, but leave control in the hands of specific business units. This approach avoids some of the bureaucratic haggling that Cisco's consolidation approach may cause. Martin Skagen, Brocade's director and chief architect, office of the CTO, finds the benefits of consolidation and partitioning great, but they create an extremely strict change control environment. Once consolidation occurs, "the moons have to align to change anything," says Skagen.
To prevent this and to keep remote SANs separate, Brocade's 48000:
- Connects remote SAN islands to its 48000 through a 7500 SAN router or the FR4-18i blade
- Allows each LSAN to retain control of the creation of user and administrator accounts
- Allows each LSAN administrator to retain control of sharing of LSAN resources
This was first published in August 2007