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Windows iscsi cli session list displays: Device Type: Unknown and Device Number : -1 connecting to Dell Equalogic (EQL) Array Volume


Article Summary: This article provides information on Windows iSCSI cli session list displays: Device Type: Unknown and Device Number : -1 connecting to Dell Equalogic (EQL) Array Volume .





Error Message:
Windows host lost access to EQL volumes. Windows iSCSI cli session list shows Device Type: Unknown and Device Number : -1


Observation:
From Array:
Group Manager shows volumes have active iSCSI connections for minutes or hours.

From Host:
Can't see EQL disk in My Computer nor Disk Manager nor Diskpart.
Microsoft iSCSI utility shows host has active connection to arrays.
c:\iSCSIcli sessionlist

From this output notice "Device Type", "Device number", "Partition Number", "Legacy Device Name" and "Device Interface"
It may show the following values:

Devices:
Device Type : Unknown
Device Number : -1
Storage Device Type : 34
Partition Number : -1
Target Name : iqn.2001-05.com.equallogic:0-8a0906-d13abec08-f1dd71b12584e086-testvol
Device Interface Name :
Legacy Device Name :
(Note: that the last 2 lines have no value)

More information about MPIO and the Microsoft Windows Storage stack can be found in this Microsoft KB article: Installing and Configuring MPIO.

Steps to troubleshoot:

Basic steps of how to get a volume to be seen in Disk Manager with MPIO:

1.When the iSCSI driver discovers a new volume, it presents this volume as a new device.

2.Plug and Play Manager detects the new device.

3.MPIO driver stack is notified of the new device.

4.MPIO driver creates pseudo device.

5.MPIO then checks to see if there are any DSM plug-in's, then associates the device with that DSM vendor.

6.Finally MPIO and DSM presents this new device to the upper layer once the device is connected and ready for I/O


Possible actions:

For clustered systems, it's a good idea to record what Volume is mapped to what Cluster disk before making changes.
A few actions that could give a positive outcome are shown below.

1. Log out of all targets, re-establish new iSCSI sessions. (To be more aggressive you could also remove Persistent Targets (Favorite Targets), then re-login.)

2. Clean up device tree by using "Diskpart".

Log out of all Targets, remove Persistent Targets. Then issue the following command in the Diskpart utility. See the Microsoft Diskpart document for more details.

Diskpart>automount scrub

"scrub - Removes volume mount point directories and registry settings for volumes that are no longer in the system. This prevents volumes that were previously in the system from being automatically mounted and given their former volume mount point(s) when they are added back to the system."

3. Remove EQL DSM plug-in to see if if problem persist. If so, it provides additional evidence to eliminate possible problems with Equallogic.

4. While MPIO is playing an important role in the Windows Storage Stack, eliminating this component is very useful. Be sure to log out of all iSCSI sessions before attempting to uninstall MPIO or the iSCSI initiator.

Windows 2003, or XP MPIO can be removed while uninstalling the iSCSI driver in Add/Remove Program.
It is also recommended that when uninstalling MPIO, you should also uninstall the iSCSI initiator at the same time.
Reboot.
Then re-install the iSCSI Initiator and MPIO.

Windows 2008 iSCSI initiator is included as a Windows driver, but MPIO is a separate Windows 2008 Feature.
To uninstall MPIO in Windows 2008, launch Server Manager, then click on Remove Feature. Uncheck MPIO to uninstall MPIO.
A reboot is required to complete this action

Check to ensure the disk can be seen in Disk Manager and accessible without MPIO. If it works, then we can attempt to reinstall MPIO again, followed by the EQL DSM.

5. Always check the NIC driver/firmware version to ensure all NICs have the same FW/driver version.
Note: Improper configuration of NIC FW/driver version can cause iSCSI and MPIO not to function properly.






Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

Код статьи: SLN156833

Дата последнего изменения: 04/23/2015 02:41 PM


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