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Delphix

KBA1613 Resolving iSCSI LUN Discovery Failures on Windows Machines

 

Problem

In some circumstances, SQL Server VDB Provisioning and Refresh operations may fail with the following error:

Description: For the virtual database "DATABASE_NAME", failed to mount iSCSI LUNs from the Delphix Engine on target host "HOSTNAME".

Action: Make sure that the iSCSI initiator is running and that the user "USERNAME" has privileges to mount LUNs on the host.

Explanation

As part of linking and provisioning, the Delphix Engine presents disks LUNs to Windows Staging and Target hosts via iSCSI. The Delphix Engine then runs scripts on these hosts (using the native diskpart utility), to find the disks and mount them on the Windows machine.

The discovery process scans all configured SCSI devices for new disks. This operation typically completes in a few seconds, but may fail if some SCSI devices connected to the Windows host do not respond.

The Windows iSCSI Initiator applet (iscsicpl.exe) may help you identify iSCSI targets that are contributing to the "failed to mount iSCSI LUNs" error.

The Reconnecting... state shows that the Windows host is currently unable to reach some of its configured iSCSI targets, slowing down discovery:

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Potential causes for the "Reconnecting..." state include:

  • The iSCSI Target is currently rebooting
  • The iSCSI Target is offline for maintenance
  • The iSCSI Target has changed IP addresses or been decommissioned, and is no longer accessible

Solution

If some iSCSI Targets are stuck in a "Reconnecting..." state because they are no longer present, they should be removed from the list of iSCSI Target Portals on the affected Windows host.

1. From the iSCSI Initiator, select the target in "Reconnecting" state and open its Properties:

clipboard_e37ff757f4a3f89f24f9df67a0456109b.png

2. From the Properties tab, identify the Portal's IP address or hostname:

clipboard_eb405194c6781f6fcd2f7b7ea49b3c41e.png

3. Use the Disconnect button to stop the iSCSI connection attempt:

clipboard_e5d2406a083dc46317c4ca8f2354b0974.png

4. From the Discovery tab, select the portal identified in Step 2, then use the Remove button to prevent future attempts to connect to that iSCSI Target:

clipboard_e610b24cbd71e1de52670c7350a12fab0.png

If an iSCSI Target is required for the operation of a VDB, the Delphix Engine will automatically re-create any necessary configuration on the next VDB Enable attempt.