Virtual Disk Not On Preferred Path

What Caused the Problem?

There is a problem accessing the RAID controller module listed in the Recovery Guru Details Area. Any virtual disks that have this RAID controller module assigned as their preferred path will be moved to the non-preferred path (alternate RAID controller module). This procedure will help you pinpoint the problem along the data path. Because the virtual disks will be moved to the alternate RAID controller module, they should still be accessible. Therefore, no action is required on the individual virtual disks.

Possible causes include:

The RAID controller module failed a manually initiated diagnostic test and was placed Offline.
The RAID controller module was manually placed Offline or is in Service Mode.
There are disconnected or faulty cables.
A Hub or Fabric switch is not functioning properly.
A host adapter has failed.
The storage array contains a defective RAID controller module.

The Recovery Guru Details area provides specific information you will need as you follow the Recovery Steps.

Caution: Possible Loss of Data Access. Do not replace the RAID controller module until you are instructed to do so. This procedure will instruct you to check the components along the connection, check the host adapters, and eventually instruct you to replace the RAID controller module, if necessary.

Caution: Electrostatic discharge can damage sensitive components. Always use proper antistatic protection when handling components. Touching components without using a proper ground may damage equipment.

Important Note

It can take several minutes for the host-based, multi-path failover driver to recognize a restored or modified preferred path. A Virtual Disk Not On Preferred Path error will be reported during this time. If you have recently modified the preferred path by clicking the Change virtual disk ownership/preferred path link from the Modify tab, or you performed a recovery procedure that has restored a preferred path, wait at least 10 minutes and run the Recovery Guru again by clicking the Recheck button. If this error is reported again, perform the Recovery Steps below.

Recovery Steps

If...

Then...

The RAID controller module was NOT manually placed Offline or in Service Mode.

Goto step 2.

The RAID controller module was manually placed Offline or in Service Mode because you were instructed to do so by a Recovery Guru procedure

Complete the steps in the Recovery Guru procedure that instructed you to place the RAID controller module offline. Fixing the associated problem should also fix this problem.

Do not continue with these Recovery Steps.

The RAID controller module was manually placed Offline or in Service Mode, but you were NOT instructed to do so by a Recovery Guru procedure

a	From the Support tab, click the Manage RAID controller modules link.
b	Click the Place RAID controller module online or offline link.
c	Place the affected RAID controller module Online.
d	Goto step 7.

If...

Then...

you have a direct attached SAS RAID enclosure

Check the external cables on both ends of the connection for loose connections.

If the connection components are OK, then goto step 4.

If there is a problem with the connection, Fix the problem, then goto step 7.

you have an iSCSI based RAID enclosure

Check for link status of the Ethernet cables between the RAID enclosure and the host server, and/or all interconnect components such as switches, routers etc.

NOTE: Crossover cables are not supported.

Goto step 3.

For an iSCSI based RAID enclosure use the information in this table to determine the action to take.

a	If the affected Virtual Disk is assigned to a host in a dual data path configuration, check iSCSI initiator settings and ensure that the host has at least one session established with each RAID controller in the iSCSI initiator software.
b	NOTE: ICMP must be enabled in MDSM in order for the iSCSI ports to respond to ping command. If the connection components are OK, then PING the iSCSI host ports. If PING is successful, then goto step 4.
c	If you are not able to ping the iSCSI ports on the RAID controller, then Check IP configuration of the host server and iSCSI host ports on the RAID enclosure. Correct any IP address conflicts. Use a standard trace route utility to identify any breaks in the network topology and fix them. Goto step 4.
d	If tagged VLAN’s are used, then verify VLAN settings in MDSM, switches and host servers. NOTE: All VLAN IDs must match.
e	If Jumbo frames are used, then verify Jumbo frame settings in MDSM, switches, and host servers. Goto step 4.

For direct attached SAS RAID or iSCSI enclosure use the information in the following table to determine the action to take.

If...	Then...
If the host has a connection to only one of the array controllers and if the virtual disk is not assigned to that controller.	Stop all I/O to the array controllers. Redistribute Virtual Disks by going to the Support Tab in the MDSM, selecting Manage RAID Controller Modules, and selecting Redistribute Virtual Disks. Change Preferred Path by going to the Modify Tab in the MDSM and selecting Change Virtual Disk Ownership/Preferred Path. Goto step 7.
If initial deployment is in a clustered environment	Redistribute Virtual Disks by going to the Support Tab in the MDSM, selecting Manage RAID Controller Modules, and selecting Redistribute Virtual Disks. Goto step 7.
The host connected to this storage array is NOT connected to any other storage arrays	Verify that its host adapter or NIC (Network Interface Card) is operational. If the host adapter or NIC is operational, the RAID controller module in the storage array is probably defective. Goto step 5. If the host adapter is defective, correct the problem, then go to step 7.
The host connected to this storage array is connected to other storage arrays	From the Summary tab, check the Storage Array drop-down menu for storage arrays showing a Needs Attention status. If one or more storage arrays connected to this host/host adapter does not have a Needs Attention status, then the RAID controller module in the storage array is probably defective. Goto step 5. If every storage array connected to this host/host adapter has a Needs Attention status, then the associated host adapter is probably defective. Fix the host adapter problem, then goto step 7.

Place the affected RAID controller module offline using the following steps. The affected RAID controller module is listed in the Details area.

a	From the Support tab, click the Manage RAID controller modules link.
b	Click the Place RAID controller module online or offline link.
c	Place the affected RAID controller module Offline.

Read all of the following steps before taking any action.

a	Click the Recheck button to rerun the Recovery Guru.
b	Select the Offline RAID Controller Module problem that is being reported in the Summary area.
c	Complete the Recovery Steps in the Offline RAID Controller Module to replace the RAID controller module.

Click the Recheck button to rerun the Recovery Guru. The failure should no longer appear in the Summary area. If the failure appears again, contact your technical support representative.

Note: Additional information on this issue may be available. Please visit the Dell support website at support.dell.com and select your product model. Choose "troubleshooting" as your tool option, then search by this procedure title.