Troubleshooting should begin at the center of the SAN—the fabric. Because switches are located between the hosts and storage devices and have visibility into both sides of the storage network, starting with them can help narrow the search path.
After eliminating the possibility of a fault within the fabric, see if the problem is on the storage side or the host side, and continue a more detailed diagnosis from there. Using this approach can quickly isolate problems.
For example, if a host cannot detect a storage device, run the switchshow command to determine if the storage device is logically connected to the switch. If not, focus first on the switch directly connecting to storage. Use your vendor-supplied storage diagnostic tools to better understand why it is not visible to the switch. If the storage can be detected by the switch, and the host still cannot detect the storage device, then there is still a problem between the host and the switch.
Here are some Link common symptoms and areas to check:
Symptom | Areas to check |
E_Port failed to come online | Correct licensing Fabric parameters Zoning Hardware or link problems |
Intermittent connectivity | Links Trunking Buffer credits |
No connectivity between host and storage | Cables SCSI timeout errors SCSI retry errors Zoning |
No connectivity between switches | Licensing Fabric parameters Zoning, if applicable Incompatible firmware versions |
No light from the port LEDs. | No signal is being detected. Check your cable and SFP |
Thanks.
