Hitachi VSP User and Reference Guide
3–10
System Components
Flash chassis
A flash chassis (factory designation FBX) is a cluster of four flash boxes as 
shown in the following illustration. It is not an actual chassis or enclosure 
surrounding the four flash boxes, but since it takes the place of a drive 
chassis, the cluster is referred to as a chassis for consistency.
The maximum number of flash modules in a flash chassis is 48. The 
minimum number of flash modules is four, one in each flash box. Flash 
modules can be added to a flash chassis in increments of four, eight, or 16, 
depending on the desired RAID configuration, as explained in the next 
section
Figure 3-8 Flash chassis