HP StorageWorks MSA 2.8 SAN Switch - Manual (Page 199)

Troubleshooting
199 Fabric OS Procedures Version 3.1.x/4.1.x User Guide
Specific Scenarios
The following sections provide specific help with some of the most common SAN
problems.
Host Can Not See Target (Storage or Tape Devices)
When a host cannot “see” its disks, the best way to troubleshoot the problem is to
start in the middle half of the data path, figure out if the problem is “above” or
“below” the data path, and keep dividing the suspect path in half until the problem
is identified.
There are two areas to check in the process of elimination:
■ Check the Logical Connection
■ Check the Simple Name Server (SNS)
■ Check for Zoning Discrepancies
■ Check Device Communication
Check the Logical Connection
Check Whether the Device is Logically Connected to the Switch
1. Enter the switchShow command.
2. Review the output and determine if the device is logically connected to the
switch:
— A device that is logically connected to the switch will be registered as an
NX_Port.
— A device that is not logically connected to the switch will be registered as
something besides an NX_Port.
— If the missing device is logically connected, move on to Check for the
Device in the SNS .
— If the missing device is not logically connected, eliminate the host
and everything on that side of the data path from the suspect list.
This includes all aspects of the host’s OS, the HBA driver settings and
binaries, the HBA Basic Input Output System (BIOS) settings, the
HBA SFP, the cable going from the switch to the host, the SFP on the
switch side of that cable, and all switch settings related to the host.
Move on to
Link Initialization Failure (Loop).