This article will introduce you to the VNXe iSCSI session troubleshooting, common problems with Microsoft iSCSI Initiator and workarounds.

iSCSI session troubleshooting:

1.     Use ping with the IP address to verify connectivity from the host to the target’s IP address. Using the IP address avoids name resolution issues.

Note: You can find the IP address for the target by selecting Settings > iSCSI Server Settingsin Unisphere.

2.     On the host, verify that the iSCSI initiator service is started.

Note: The iSCSI service on the iSCSI Server starts when the VNXe system is powered up.

3.     In the Microsoft iSCSI Initiator, verify the following for the VNXe target portal:

·         IP address(es) or DNS name of the VNXe iSCSI Server with the host’s virtual disks.

Note: For a host running PowerPath or Windows native failover, VNXe target portal has two IP addresses.

·         Port is 3260, which is the default communications port for iSCSI traffic.

4.     Verify that the iSCSI qualified names (IQN) for the initiators and the iSCSI Server name for the target are legal, globally unique, iSCSI names.

Note: An IQN must be a globally unique identifier of as many as 223 ASCII characters.

For a Windows host initiator - You can find this IQN on the General tab of the Microsoft iSCSI initiator.

5.     If you are using optional CHAP authentication, ensure that the following two secrets are identical by resetting them to the same value:

·         The secret for the host initiator in the Microsoft iSCSI Software Initiator or the Linux open-iscsi driver.

·         The secret configured for the host initiator on the VNXe iSCSI Server.

6.     If you are using optional mutual CHAP authentication, ensure that the following two secrets are identical by resetting them to the same value:

·         The secret for the host initiator in the Microsoft iSCSI Software Initiator or the Linux open-iscsi driver.

·         The secret for the iSCSI Server on the VNXe iSCSI Server.

Microsoft iSCSI Initiator common problems and workarounds:

Problem 1:

Initiator cannot refresh its targets list.

Symptom:

If you use iSNS and an initiator is disconnected from the network, the initiator may not refresh its target list. When attempting to refresh the target list, the initiator logs the iSNS error auth unknown (0x6) to the Windows Event Log.

Workaround:

1. Select Windows Administrative Tools > Services.
2. Stop and restart the Microsoft iSCSI Initiator.

Problem 2:

Login problems occur when you use iSNS for target discovery.

Symptom:

When you configure the initiator with iSNS target discovery, it can intermittently fail to log in to a target with the following error message:

The target name is not found or is marked as hidden from login.

Workaround:

The Microsoft iSCSI Initiator eventually recovers from this situation. To speed up the process, refresh the target list a few times until the target in question is discovered.

Problem 3:

Initiator messages fill up the Windows Event Log.

Symptom:

If the initiator has an active session with a VNXe iSCSI Server and the iSCSI Server becomes unavailable, then the initiator logs multiple messages to the Windows Event Log. If multiple virtual disks are configured for each target, the messages that the initiator generates can quickly fill the log.

Workaround:

To avoid this situation, log out all connected initiators before bringing the target down for its scheduled downtime.

Problem 4:

Cannot write to a filesystem on a VNXe storage resource connected to the host.

Symptom:

Filesystem is read-only.

Workaround:

1. Verify that set the correct registry values. 
2. Verify that correctly configured Microsoft iSCSI Initiator and connected to the VNXe iSCSI Server.

                                                                                                                                                                                                                                                                             Author: Leo Li

             

iEMC APJ

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