Specifications

Chapter 2. Architecture and technical overview 61
Draft Document for Review May 12, 2014 12:46 pm 5102ch02.fm
The EXP24S SFF Gen2-bay drawer can be ordered in one of three possible mode settings,
configured by manufacturing (not customer set-up), of 1, 2, or 4 sets of disk bays.
With IBM AIX and Linux, the EXP24S can be ordered with four sets of six bays (mode 4), two
sets of 12 bays (mode 2), or one set of 24 bays (mode 1).
There are six SAS connectors on the rear of the EXP24S drawer to which to SAS adapters or
controllers are attached. They are labeled T1, T2, and T3; there are two T1, two T2, and two
T3 connectors. Figure 2-24 shows the rear connectors of the EXP24S drawer.
򐂰 In mode 1, two or four of the six ports are used. Two T2 ports are used for a single SAS
adapter, and two T2 and two T3 ports are used with a paired set of two adapters or dual
adapters configuration.
򐂰 In mode 2 or mode 4, four ports are used, two T2 and two T3, to access all SAS bays.
Figure 2-24 EXP24S SFF Gen2-bay drawer rear connectors
An EXP24S drawer in mode 4 can be attached to two or four SAS controllers and provide
high configuration flexibility. An EXP24S in mode 2 has similar flexibility. Up to 24 HDDs can
be supported with any of the supported SAS adapters or controllers.
Any EXP24S order includes the EXP24S drawer no-charge specify codes to indicate to IBM
manufacturing the mode to which the drawer should be set. The drawer is delivered with this
configuration. If multiple EXP24S drawers are ordered, mixing modes should not be within
that order. There is no externally visible indicator regarding the drawer's mode.
For details about the SAS cabling, see “SAS cabling for the 5887 drawer” in the information
center:
http://pic.dhe.ibm.com/infocenter/powersys/v3r1m5/index.jsp?topic=/p7had/p7hadsasc
abling.htm
Notes:
򐂰 The modes for the EXP24S drawer are set by IBM manufacturing. There is no option to
reset after the drawer is shipped.
򐂰 One #5887 EXP24S drawer in mode 1 can be attached to the two SAS ports on the
rear of the Power S822 server using two SAS YO cables such as #ECBT, #ECBU,
#ECBV, or #ECBW cable options.
򐂰 Either SSDs or HDDs can be placed in this drawer, but SSDs and HDDs cannot be
mixed in this drawer.
򐂰 Up to 14 EXP24S drawers can be attached to the Power S822 server.
򐂰 Longer distance SAS cables are thicker and can fill the cable management arm more
quickly.