Link rate leds, Data transfer rates for drive modules – IBM System Storage Subsystem DS5020 User Manual
Page 167
CAUTION:
Do not change the link rate setting while the storage subsystem is running.
Changing the link rate setting while the storage subsystem is running could
cause drives to fail. You must power down the storage subsystem and
storage expansion enclosures before changing the link rate setting.
Attention:
All devices on the loop must have the same data transfer rate, which
means that you must set the link rate on the storage expansion enclosure to the
same rate as the storage subsystem to which it is connected. Information about
supported DS4000 storage subsystems can be obtained from the certified
Compatibility Matrix, which can be found at the following Internet location:
Table 19. Data transfer rates for drive modules
Link rate
switch
setting
Storage subsystem
with 2 GB drives
Storage subsystem with
4 GB drives
Storage subsystem with
mixed drives
4 Gbps
Drives do not come
online.
Drives work in 4 Gbps
mode.
2 GB drives do not come
online.
4 GB drives work in 4 Gbps
mode.
Use the following procedure to check the current setting of the data transfer rate
and change it, if necessary:
1. Complete the power-off sequence described in “Turning off the storage
subsystem” on page 109 ensuring that the DS5020 storage subsystem is
turned off before any attached storage expansion enclosures.
2. Locate the link rate indicator LEDs. Figure 81 shows the location of the link
rate indicator lights on the back of the storage subsystem.
Link
Rate
LEDs
Two on = 4 Gbps
One on = 2 Gbps
Figure 81. Link rate LEDs
Chapter 5. Replacing components
137