VTL - SANtricity/CAM is reporting LUNs not on preferred path

Asset ID:	1-72-1015755.1
Update Date:	2011-05-03
Keywords:

Solution Type Problem Resolution Sure

Solution 1015755.1 : VTL - SANtricity/CAM is reporting LUNs not on preferred path

Applies to:

Sun StorageTek VTL Plus Storage Appliance - Version: 1.0 - Build 1323 to 2.0 - Build 1656 - Release: 1.0 to 2.0
Sun StorageTek VTL Prime System - Version: 1.0 - Build 1813 to 1.1 - Build 2076 [Release: 1.0 to 1.0]
Sun StorageTek VTL Storage Appliance - Version: 4.0 - Build 1221 to 4.0 - Build 1221 [Release: 4.0 to 4.0]
All Platforms
***Checked for relevance on 03-05-2011***

Symptoms

- AVTs occurring
- Message: Volume not on preferred path due to AVT/RDAC failover
- LUNs are showing in VTL console on different preferred path than in SANtricity
- SANtricity is reporting LUNs not on preferred path
- Message: Automatic volume transfer completed

Changes

N/A

Cause

This is normal path failover processing for VTL when there is a temporary FC path interruption from the VTL server to the VTL backend disk.

Solution

Below describes the steps to take to troubleshoot and resolve "not on preferred path" messages.

First, collect support logs from disk array and have them reviewed for errors (If necessary, open a task with the OS Midrange Disk group)

1. If disk array has errors, correct as recommended by Disk group
* If only errors are "not on preferred path" messages, redistribute the volumes (in SANtricity, select 'Advanced', 'Recovery', then 'Redistribute Volumes')

2. If disk array is optimal, perform the following to change the scsi aliasing manually in the VTL GUI, so the proper LUNs are on the HBA's plugged into the controllers:

A. From VTL Console GUI, expand tree under Physical Resources>Storage Devices>Fibre Channel Devices, right click on a disk/LUN in question, select "Properties", then select I/O Path tab. From this screen, highlight a group and use the arrows on the right side of window to move the path up or down in order (top being preferred path).

B. Rediscover/rescan the devices (from VTL Console, right click on Physical Resources and select rescan).
Note a reboot will accomplish this as well.

Additional Information
The following describes the "I/O Pathing" procedure that is to be done when VTL is first installed.
Change the scsi aliasing manually in the VTL GUI, so the proper LUNS are on the HBA's plugged into the controllers. For example, identify the 2 HBA's from the VTL you have plugged in ports A1 and A2 on controller A of the array. This might be represented as 1:0:0:x and 3:0:0:x (x=the lun number from the disk).
Just move them around (clicking up and down arrows) to make the 'A" volumes attached to the HBA's connected to the A controller. If you have 10 volumes, put 5 on each HBA attached to the A controller. Do the same for the B controller HBA's as well. You will need to reboot the VTL when your done, or rediscover the devices by doing a rescan on the HBA's in the GUI. Once you have them distributed for both controllers on all 4 HBA's, go into SANtricity and redistribute the volumes to the preferred path. This will clean up the AVT issues you have.

To see how VTL has the paths set, look in ipstor.conf file and search for the SCSIAliasing section. The first "DeviceAlias adapter=" is the primary or preferred path set in VTL.

            </IPStorPartition>
            <SCSIAddress adapter="5" id="1" lun="0"/>
            <SCSIAliasing>
              <DeviceAlias adapter="5" id="1" lun="0" groupNo="0" controllerNo="0"/>
              <DeviceAlias adapter="1" id="1" lun="0" groupNo="1" controllerNo="0"/>
              <DeviceAlias adapter="4" id="1" lun="0" groupNo="2" controllerNo="1"/>
              <DeviceAlias adapter="0" id="1" lun="0" groupNo="3" controllerNo="1"/>
            </SCSIAliasing>
            <Geometry startingSector="12416" endingSector="2097151"/>
            <InquiryString>0000053245004032STK     FLEXLINE 380    0619</InquiryString>
            <Comments/>
          </PhysicalDev>
          <PhysicalDev name="STK:FLEXLINE 380" type="Direct-Access" owner="denvtl01" guid="0a1e0a39-0000-288b-740c-32c9306149b0" fsid="fa1c0401-838b-27da-fc8d-04a63c56e954" key="f9a1218c-3c22-43cd-8dc9-f25f3042f788" queueDepth="255" connectionType="fc" controllerType="lsi" primaryID="53503634353039313430000000000000" alternateID="53503634383131373237000000000000" lunType="1">
            <IPStorPartition/>
            <SCSIAddress adapter="1" id="1" lun="1"/>
            <SCSIAliasing>
              <DeviceAlias adapter="0" id="1" lun="1" groupNo="2" controllerNo="1"/>
              <DeviceAlias adapter="4" id="1" lun="1" groupNo="3" controllerNo="1"/>
              <DeviceAlias adapter="1" id="1" lun="1" groupNo="0" controllerNo="0"/>
              <DeviceAlias adapter="5" id="1" lun="1" groupNo="1" controllerNo="0"/>

Also refer to the "Optimizing VTL Pathing" best practices doc. Contact VTL support for copy.

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Previously Published As
STKKB74741

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