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How to Troubleshoot the Fault that Paths of LUNs the S5500 Storage Device Maps to the Host

Publication Date:  2012-07-20 Views:  219 Downloads:  0

Alarm Information


Handling Process

Step 1
1. Check whether domains are properly configured on the FC switch. Assist the customer to log in to the FC switch and check whether the storage port and server port on the FC switch are allocated in the same domain. The first FC port on controller B of the S5500 that is connected to FC switch 2 is not in the same domain controller of the host port; therefore, two paths to FC switch 2 are lost.
2. Allocate the first FC port on controller B in the same domain of the host port and then find that the number of paths increases from four to six (two more paths are still lost).
Step 2
1. Check the optical fibers at the rear side of the S5500. Due to the customer’s misoperation, the input and output connectors of the optical fiber of the second FC port on controller B are conversely connected, causing that the indicator of the second FC port is off and two paths are lost.
2. Correct the connection of the input and output connectors of the optical fiber, the number of the paths changes from six to eight (normal).
Step 3
After the paths become normal and customer’s services are recovered, the database on the host reads data from the S5500 at a slow rate. The cause is that the customer restarts the host without stopping the database. Ask the customer to restart the host after stopping the database. After that, the read rate becomes normal.

Root Cause

The log indicates that the FC switch cannot communicate with controller B of the S5500 through the second path, that is, the path between the second FC port on controller B of the S5500 and FC switch 2 is lost. The possible cause is incorrect domain configuration on the FC switch, faulty FC port on the S5500, or faulty optical transceiver.


For the problem that the LUN paths between the storage device and the server are lost, the troubleshooting procedure is as follows:
1. Check whether domains on the FC switch are properly configured.
2. Check whether the link indicator of the FC port is on.
3. Check whether the rate of the FC port is correct.
4. If possible, directly connect the host to the storage device without a FC switch. If four paths can be discovered on the host, it indicates that the connection or configuration of the FC switch is defective.
5. Remove and insert the optical fibers on the storage device in turn and observe the host each time.