Appendix D. Back-To-Back Racking; Product Description - HP Surestore Disk Array 12h - And FC60 Service Manual

Appendix D. Back-to-Back Racking

This appendix explains how to install disk arrays back-to-back in either a 1.6-meter rack (C2786A) or a 2.0
meter rack (C2787A). The following information is included:

Product description

Installation
Troubleshooting
Removal and replacement
Specifications
Product Description
Customers may obtain maximum disk storage capacity with a minimum use of floor space by filling their
Hewlett-Packard computer/instrument racks completely with the maximum number of array enclosures.
This solution is known as back-to-back racking, because both front and back areas of the rack are used, and
the disk arrays are oriented "back-to-back" in the rack.
Back-to-Back installation of disk arrays requires several modifications be made to the rack prior to
installing the additional arrays. These modifications include:
Installation of power upgrade kit, three 19" PDU assemblies (replacing the existing 56" PDUs),
Installing a high volume exhaust fan assembly, and
Removing the rear rack door and hardware
Field upgrade kits are available for the above modifications and need to be available prior to beginning the
installation (see Table 19. Upgrade Kits and Components).
Prior to modifying the rack for back-to-back installation you need to determine if the maximum number of
disk arrays can be installed. Six disk arrays completely fill a 2.0-meter rack and four disk arrays fill a 1.6
meter rack, known as high-density configuration. Depending on the service access method, the maximum
number of arrays that can be installed varies. If the rack is located to allow a side panel to be removed for
service access (for example, if the rack is located at the end of a row or can be rolled out) then the rack can
be filled completely (high density). If the rack is situated such that side access is not possible then one
position (one disk enclosure space) must remain open to allow for service access (see
NOTE The 1.6 meter rack (C2786A) has a total height of 32 EIA units and the 2-meter rack
(C2787A) has a total height of 41 EIA units. (One EIA unit is equal to 1.75 inches or 44.45 mm.)
The disk array enclosure has a height of 13 EIA units.
Figure 49).
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