Fibre Channel (SAN)

Reply
Occasional Contributor
Posts: 10
Registered: ‎09-22-2009

SCSI errors on host

we are seeing intermittent scsi errors on hosts that use the ISL to get to the target. If the initiator does not have to go over the ISL we do not see these scsi errors.

what do i need to look for in troubleshooting this ?

Frequent Contributor
Posts: 140
Registered: ‎02-27-2008

Re: SCSI errors on host

Hi gananthkrishna

Log into the switch which your host is connected to and run the following command

"porterrshow"

Copy the output up here and we'll take a look.

Regards

David

Super Contributor
Posts: 260
Registered: ‎04-09-2008

Re: SCSI errors on host

David is right, but I have yet another suggestion.

Since you suspect the ISL, run the command

fabriclog -s

Look for ports which are flapping.

Frequent Contributor
Posts: 76
Registered: ‎02-13-2010

Re: SCSI errors on host

Hi Gan,

Just a starting point:

Are you using Trunking on your ISLs or Exchanged-based routing, Port-based routing?

Have you set In Order Delivery? type "iodshow" to see.

What is the FOS version you are using on your switches? Check if you have compatible FOS versions on your switches.

If you're in interop mode with McData switches that may also have some conditions to check.

If you're getting SCSI errors which is a high-level layer on the FC stack then I would bet more to some host-side issue. So take a look at your multi-pathing software, patches, OS issues, etc.

Check your compatibility list between disk array-HBA-Server OS-application-Volume Manager, etc. This are typical causes of these kind of problems more than the switch itself.

Cheers

Occasional Contributor
Posts: 10
Registered: ‎09-22-2009

Re: SCSI errors on host

iodshow is not set. we are using trunking on the ISL.  FOS version used is 6.2.1b. Its a brocade native fabric.

we are using trunking on the ISL.

We did see a bunch of ports (around 10) with high error rates and are fixing those. Since then the scsi error rates have died down.

Question is: Could a single port or a handleful of ports with issues cause fabricwide issues and timeouts for host?

Frequent Contributor
Posts: 76
Registered: ‎02-13-2010

Re: SCSI errors on host

Hi Gan,

This kind of condition could cause the flood of a lot of RSCNs and therefore can potentially generate a fabric wide issue. So yes! Take a look at the cables and also at the SFPs that may have gone bad.

Good luck with the issue and thanks for posting how did you address the problem.

Cheers!

Super Contributor
Posts: 260
Registered: ‎04-09-2008

Re: SCSI errors on host

answer is: Yes a single flapping ISL port can cause fabric wide issues. You need to configure port fencing to prevent this catastrophe.

Join the Community

Get quick and easy access to valuable resource designed to help you manage your Brocade Network.

vADC is now Pulse Secure
Download FREE NVMe eBook