Chapter 5: Troubleshooting
Isolate a Host-side CNC Connection Fault
QX and QXS Setup Guide
139
Host-side Connection Troubleshooting Featuring CNC
Ports
The procedure below pertains to the controller I/O modules (in the RAID chassis) employing SFP
transceiver connectors in 4/8/16 Gbit FC, 10GbE iSCSI, or 1 Gb iSCSI host interface ports. In the following
procedure, “SFP and host cable” is used to refer to any of the qualified SFP options supporting CNC ports
used for I/O or replication.
1. Halt all I/O to the storage system (see Stopping I/O
).
2. Check the host activity LED.
If there is activity, halt all applications that access the storage system.
3. Check the Cache Status LED to verify that the controller’s cached data is flushed to the drives.
l
Solid – Cache is dirty (contains unwritten data) and is not writing to drive.
l
Blinking – Cache data is being written to CompactFlash.
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Flashing at 1/10 second on and 9/10 second off – Cache is being refreshed by the supercapacitor.
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Off – Cache is clean (no unwritten data).
4. Remove the SFP and host cable and inspect for damage.
5. Reseat the SFP and host cable.
Is the host link status LED on?
l
Yes – Monitor the status to ensure that there is no intermittent error present. If the fault occurs again,
clean the connections to ensure that a dirty connector is not interfering with the data path.
l
No – Proceed to the next step.
6. Move the SFP and host cable to a port with a known good link status.
This step isolates the problem to the external data path (SFP, host cable, and host-side devices) or to
the controller module port.
Is the host link status LED on?
l
Yes – You now know that the SFP, host cable, and host-side devices are functioning properly.
Return the SFP and cable to the original port. If the link status LED remains off, you have isolated
the fault to the controller module’s port. Replace the controller module.
l
No – Proceed to the next step.
7. Swap the SFP with a known good one.
Is the host link status LED on?
l
Yes – You have isolated the fault to the SFP. Replace the SFP.
l
No – Proceed to the next step.
8. Re-insert the original SFP and swap the cable with a known good one.
Is the host link status LED on?
l
Yes – You have isolated the fault to the cable. Replace the cable.
