Symptom
RAID Admin reports "RAID Controller not ready".
If you troubleshoot by swapping each controller module into the other module's slot, the symptom follows the controller module, not the slot.
Solution
Follow these steps to fix or isolate the issue. Check in between steps to see if the issue was resolved, or if you need to continue to the next step. Be sure to give RAID Admin enough time to update status before moving to the next step.
1. Quit the RAID Admin application and open it again. If the message does not reappear, it was caused by a refresh issue that did not update the message field.
2. Remove the Xserve RAID from the monitoring list and add it again. You may find that the Xserve RAID has acquired a new DHCP address (if set to DHCP) that would account for the connection failure. Rediscover the Xserve RAID and add it back to the monitoring list. If the Xserve RAID has the same IP address, removing and adding it back to the monitoring list may still be a helpful step to perform.
3. Look in the Component tab for the Xserve RAID having a component issue. If one of the controller modules has a warning, go to the System menu and restart that controller's coprocessor. This step does not take your data offline.
4. Quit the RAID Admin application. Pull both cache backup batteries slightly out from the Xserve RAID. Shut the RAID down, if possible, by holding the power button for five seconds.
Warning: This step causes the RAID to go offline. Be sure any other computers are disconnected from RAID volumes when you perform this step.
If the power button does not shut the RAID down, you will need to disconnect both power cables. After ten seconds, use the power button to turn on the RAID. After the RAID is on and the status LEDs on the front are solid green, the cache backup batteries may be reinstalled. Open the RAID Admin application and test the issue again.
If none of the steps listed above resolves the issue, contact Apple for further assistance.
Additional information
The "RAID Controller not ready" message is a general communications alert, which can indicate different causes.
The most common cause is that the RAID controller is restarting. This message is normal to see temporarily if the controller is restarting. The message only indicates an issue if the message is persistent.
This message does not in any way affect the data on the hard disks. In most cases the data on the hard disks is still accessible; only in very rare cases will the data be offline.