Dell PowerVault ME4 Series Storage System Deployment Guide

Isolating a controller module expansion port connection fault

During normal operation, when a controller module expansion port is connected to an expansion enclosure, the expansion port status LED is green. If the expansion port LED is off, the link is down.

1. Halt all I/O to the storage system. See “Stopping I/O” in the Dell PowerVault ME4 Series Storage System Owner’s Manual.
2. Check the host activity LED.
   If there is activity, stop all applications that access the storage system.
3. Check the Cache Status LED to verify that the controller cached data is flushed to the disk drives.
   • Solid – Cache contains data yet to be written to the disk.
   • Blinking – Cache data is being written to CompactFlash in the controller module.
   • Flashing at 1/10 second on and 9/10 second off – Cache is being refreshed by the supercapacitor.
   • Off – Cache is clean (no unwritten data).
4. Remove expansion cable and inspect for damage.
5. Reseat the expansion cable.

   Is the expansion port status LED on?

   • Yes – Monitor the status to ensure that there is no intermittent error present. If the fault occurs again, clean the connections to ensure that a dirty connector is not interfering with the data path.
   • No – Proceed to the next step.
6. Move the expansion cable to a port on the controller enclosure with a known good link status.

   This step isolates the problem to the expansion cable or to the controller module expansion port.

   Is the expansion port status LED on?

   • Yes – You now know that the expansion cable is good. Return the cable to the original port. If the expansion port status LED remains off, you have isolated the fault to the controller module expansion port. Replace the controller module.
   • No – Proceed to the next step.
7. Move the expansion cable back to the original port on the controller enclosure.
8. Move the expansion cable on the expansion enclosure to a known good port on the expansion enclosure.

   Is the host link status LED on?

   • Yes – You have isolated the problem to the expansion enclosure port. Replace the IOM in the expansion enclosure.
   • No – Proceed to the next step.
9. Replace the cable with a known good cable, ensuring the cable is attached to the original ports used by the previous cable.
   Is the host link status LED on?

   • Yes – Replace the original cable. The fault has been isolated.
   • No – It is likely that the controller module must be replaced.