Data Domain DD9800 System Installation and Storage Expansion Guide

Installing the expansion shelves into the racks

1. From the front of a rack, lift the shelf to the designated rack location.
2. Add shelves to the racks in order, one at a time, from the bottom of a rack to the top filling each string in that rack before going to the next.
   NOTE Strings in add-on racks may connect to the same string number in other racks.
   Shelves are added in the order V1.1, V1.2, V1.3, V1.4, V2.1, V2.2, and so on. Shelves are labeled VN.M. VN refers to string "N" and the "M" is the number of the shelf in the string. For example, V3.2 refers to the second shelf in the third string.
3. Secure each expansion shelf in the rack.
4. When installing an SSD shelf for Data Domain metadata on flash:
   • The SSD shelf counts towards the total number of shelves connected to the system.
   • Data Domain recommends installing the SSD shelf in the V1.1 positon, but if that is not possible, the shelf can be placed in a different location in the rack so long as cables of sufficient length are available.
     NOTE V1.1 is recommended for better performance because this will the 1^st hop where data will be written. If the SSD shelf is connected to the last enclosure in a chain, then each read/write request has to go through many hops, which introduces latency issues when compared to when the SSD shelf is on the 1^st shelf of a chain.