Expansion Enclosures Not Cabled Correctly

What Caused the Problem?

There are expansion enclosures in the storage array that are not cabled correctly because they have EMM modules that must be cabled sequentially together. The Recovery Guru Details area provides specific information you will need as you follow the recovery steps.

Important Notes

Using an incorrect cabling configuration (where the reported expansion enclosures are not cabled sequentially together) can reduce the RAID RAID controller module's performance and cause advanced features in the EMM to be disabled.
Even if the expansion enclosures listed in the Details area are stacked sequentially in a cabinet, it does not necessarily mean that they are cabled sequentially together.
You can re-cable the EMMs in the affected expansion enclosures with power applied to the storage array as long as you re-cable one physical disk channel at a time (see the second Caution statement below).
In general, you should always connect expansion enclosures with the same EMMs in sequential order. For example, if you have 4 expansion enclosures (two enclosures with EMM type 1 and two enclosures with EMM type 2), then you should cable them as follows: EMM type 1--EMM type 1--EMM type 2--EMM type 2.

Caution: Electrostatic discharge can damage sensitive components. Always use proper antistatic protection when handling components. Touching components without using a proper ground may damage the equipment.

Caution: Potential loss of data access. If the affected expansion enclosures are connected to the RAID controller module using multiple physical disk channels, make sure that you re-cable only one physical disk channel at a time. Failure to do so will result in loss of access to the data on these physical disks.

Recovery Steps

Physically locate the expansion enclosures listed in the Details area of this procedure.

Trace the physical disk channel cables from the RAID controller module to the associated EMM modules on the affected expansion enclosures.

Important: If the expansion enclosures are cabled to the RAID controller module using multiple physical disk channels, make sure that you re-cable only one physical disk channel at a time (see Caution statement above).

3	Record the current cabling scheme by noting (2) the entry points into the expansion enclosures from the physical disk channels on the RAID controller module and (2) how the affected expansion enclosures are connected to the other expansion enclosures in the storage array
4	Starting with one of the physical disk channels, disconnect the cables to the EMMs in the affected expansion enclosures.
5	Reconnect the cables making sure that the EMMs in the affected expansion enclosures are cabled sequentially together and that there are connections to the other expansion enclosures in the storage array.
6	If you have more than one physical disk channel, repeat steps 4 and 5 in the reverse order that you connected the first physical disk channel (for example, if you connected the first physical disk channel to expansion enclosures 1, 2, 3, and 4; then, connect the second physical disk channel to expansion enclosures 4, 3, 2, and 1). Then, go to step 7.
7	Click the Recheck button to rerun the Recovery Guru. The failure should no longer appear in the Summary area. If the failure appears again, recheck your cabling and, if necessary, contact your technical support representative.