[T Series]Removing and Reinserting a Fiber Cable

Publication Date:  2012-07-19 Views:  112 Downloads:  0
Issue Description
Product and version information:
S5500T V100R001 V100R002
S5600T V100R001 V100R002
S6800T V100R001 V100R002
Application server operating system: Linux 2.6.18-128.el5PAE

The storage device and the application server were on an FC switch connection network as shown in Figure1.
 

    Figure 1 FC switch connection network

  • In this networking environment, removing and reinserting the fiber cable that connects the FC host port to the switch interrupted the application server's DD read/write services.

    On the ISM menu bar, choose Event > Event Management. In the Event Management dialog box the fault information indicates an FC host port link-down.

Alarm Information
None
Handling Process
This problem cannot be resolved. The only workaround is to restart the DD read/write services.
Root Cause
We ran the same test using an EMC storage device on the same network, and the same symptom occurred.
It is concluded that the DD service interruption was due to an inherent mechanism defect on the Linux 2.6.18-128.el5PAE application server.
Suggestions
We found in the test that some application servers and programs cannot properly handle intermittent FC link-downs. These restraints lead to service interruption. To ensure physical link reliability in service running process:
Do not unnecessarily remove and reinsert fiber cables or optical transceivers.
Do not unnecessarily change the rates or topology modes of FC host ports and switch ports.

END