IBM DS4800 - Intermixing the EXP810 and EXP710 in the same Drive Channel; Controllers

Table 3. Maximum number of storage expansion enclosures (continued)
Enclosure type
Maximum number of
enclosures in a redundant
DS4800 drive channel pair
Maximum number of
enclosures in a DS4800
subsystem
EXP710 and EXP810 7
1
14 (or 15)
2
1
The intermix of EXP100 and EXP810 storage expansion enclosures behind a DS4800
subsystem is not currently supported. Please contact IBM reseller and representatives for
such support in the future.
2
The value 15 assumed that one of the redundant DS4800 drive channel pairs must have
only EXP710 enclosures attached.
Notes:
1. Important: DS4000 EXP700s are not supported by the DS4800 unless they
have been upgraded (with the DS4000 EXP700 Models 1RU/1RX
Switched-ESM Option Upgrade Kit) to have the same internal switched
capabilities as the DS4000 EXP710.
2. The DS4800 does not support the attachment of storage expansion enclosures
operating at 1 Gbps, such as the EXP500.
Intermixing the EXP810 and EXP710 in the same drive channel
You can intermix the EXP810 and EXP710 in the same drive channel, but the Link
Rate switch for all storage expansion enclosures in the intermixed drive channel
must be set to 2 Gbps.
There are maximum limits to the number of fibre channel hard drives that you can
configure in redundant drive channel pairs. The maximum number of drives dictates
a fixed number of supported EXP710 and EXP810 drive enclosure combinations.
Table 4 lists the numbers of EXP710 and EXP810 storage expansion enclosures
that you can combine for use in a single redundant drive channel/loop pair. Table 4
assumes that a DS4000 storage subsystem is generally capable of addressing the
maximum of 112 fibre channel hard drives for each redundant drive channel pair.
Table 4. Supported EXP810 and EXP710 enclosure combinations per redundant drive
channel pair
Number of
EXP810s
Number of
EXP710s
Total number
of drives in
EXP810s
Total number
of drives in
EXP710s
Total number of drives
in a mixed EXP710 and
EXP810 drive channel
0 8 0 112 = 112
1 6 16 84 = 100
2 5 32 70 = 102
3 4 48 56 = 104
4 3 64 42 = 106
5 2 80 28 = 108
6 1 96 14 = 110
7 0 112 0 = 112
Controllers
The DS4800 has two RAID controllers. Both controllers are identical and
interchangeable. The controllers install from the rear of the storage subsystem. The
10 IBM System Storage DS4800 Storage Subsystem: Installation, User’s, and Maintenance Guide