The following are allowable configurations for additional DE3-24 disk shelf pairs:
20 SSD or HDD data drives and up to 4 SSD log or read cache devices
20 SSD or HDD data drives and 2 SSD log or read cache devices
24 SSD or HDD data drives
The placement of DE3-24 disk shelves follows this priority:
DE3-24 disk shelves with SSD log devices
DE3-24 disk shelves with SSD read cache devices
DE3-24 disk shelves without SSD log or read cache devices
In all cases, the placement of SSD log devices takes precedence over SSD read cache devices, and the placement is always in disk shelf pairs. The only exception where pairs are not installed is for an expansion “half-rack” such that only one disk shelf is added to the expansion cabinet, for a total of five disk shelves. SSD log and read cache devices can be installed into DE3-24 disk shelves in slots 20, 21, 22, and 23 in that order of priority.
Figure 692 DE3-24P Disk Shelf Drive Locations (Front View)
Figure 693 DE3-24C Disk Shelf Drive Locations (Front View)