Prerequisites for 3DC cascade

• (VSP G1000, G1500, and VSP F1500) The VSP G1000, VSP G1500, VSP F1500, VSP, USP V/VM, and VSP G800 can be used at the primary, intermediate, and secondary sites.

• (VSP Gx00 models and VSP Fx00 models) One VSP G800, VSP F800, VSP G1000, VSP G1500, or VSP F1500 is required for each site. HUS VM is not supported in 3DC cascade configurations.

• If a site has multiple storage system, 3DC cascade cannot be configured.

• CCI is recommended at all the sites.

• Device Manager - Storage Navigator is required at all sites.

• The primary site requires the following:

• Host application

• TC

• TC primary volume (P-VOL), the primary production volume

• The TC P-VOL fence level (Primary Volume Fence Level) must be Data or Secondary Volume Data.

• The intermediate site requires the following:

• TC

• UR

• TC S-VOL = UR P-VOL

• UR master journal volume

• The secondary site requires the following:

• UR

• UR S-VOL

• UR restore journal volume

• Differential data is used to resynchronize a suspended TC or UR pair.

• When the TC pair is resynchronized, the UR pair in PAIR or COPY status is automatically split by the system.

• (VSP G1000, G1500, and VSP F1500) 3DC cascade is not supported for multiple primary and secondary storage systems. The UR or TC pair in this configuration would be suspended when the status became PAIR or COPY.

• (VSP G1000, G1500, and VSP F1500) The response time for host I/Os will be the response time for TC operation plus the creation time of journal data in the intermediate site.

• (VSP G1000, G1500, and VSP F1500) The utilization rate on the primary site with a 3DC cascade configuration is higher than if UR and a TC systems are used independently.