Maximum Number Of Exp3512 And Exp3524 Storage Enclosures With Controller Firmware Level 7.75.Xx.xx And Earlier; Redundant Drive Channel Pair - IBM DS3500 Installation, User's, And Maintenance Manual

Table 11. Maximum number of EXP3512 and EXP3524 storage enclosures with controller
firmware level 7.77.xx.xx and later (continued)
DS3512
EXP3512 11 10
EXP3524 2 2
or
EXP3512 7 6
EXP3524 4 4
or
EXP3512 3 2
EXP3524 6 6
Table 12 shows the maximum number of EXP3512 and EXP3524 storage enclosures
that can be attached to either a DS3512 or a DS3524 storage subsystem and not
exceed the 96 total disk drives with controller firmware level 7.75.xx.xx and earlier.
Any combination of EXP3512 or EXP3524 storage enclosures can be attached to a
DS3512 or a DS3524 as long as the total number of disk drives does not exceed 96.
Table 12. Maximum number of EXP3512 and EXP3524 storage enclosures with controller
firmware level 7.75.xx.xx and earlier
DS3512
Storage Quantity
enclosures
EXP3512 7 5
EXP3524 0 1

Redundant drive channel pair

Each storage controller on the DS3500 has a drive expansion channel that contains
an x4 SAS port. The storage enclosures that are connected to this connector form a
drive channel. You can install a maximum of 96 drives in one drive channel. In a
dual-controller DS3500, one drive channel from each controller combines to form a
redundant drive-channel pair.
Figure 38 on page 50 shows an example of a redundant drive-channel pair. If any
component of the drive channel fails, the controllers can still access the storage
enclosures in the redundant drive-channel pair.
Note: In storage enclosures that are connected to a dual-controller storage
subsystem, you must install the optional second ESM to support dual redundant
drive paths.
9 8 EXP3524
3 3 EXP3512
5 4
5 5
1
7
Storage
enclosures
3 1 EXP3524
2 3 EXP3512
Chapter 3. Cabling the storage subsystem and storage enclosure
DS3524
3 2 1
8 10 12
DS3524
Quantity
3 2 1 0
0 2 4 6
49