iSCSI Initiator Dropping

Posted on 2008-11-19
Last Modified: 2013-12-01
We have an new HP server with 6 GB of memory and quad core 64-bit processor running Microsoft Hyper-V on windows 2008.  We have one Guest OS, which is a Windows 2008 OS running the file server role of server core.  In the Guest OS we are running Backup Exec12 agent to backup our data.  The data is connected to a HP MSA 2012i SAN via iSCSI.  The connection to the SAN is via two nics that are teamed and on a separate VLAN dedicated to the SAN.  All switching is gigabit.  

The backup server happens to be the host Hyper-V server.  The host and the guest each have a dedicated nic that is connected to a server vlan.  The host server is running Backup Exec and backs up the guest via the agent.  

When the backup runs, we are seeing relatively slow speed and after a period of time the iSCSI Initiator reports that it has lost connection to the disk.  A moment later it returns.  This behavior seems to repeat itself throughout the backup and often the backup will just fail.

We are hoping someone might be able to clue us into why the iSCSI initiator might be dropping out.  We are not seeing any errors on the HP MSA SAN nor on the switching devices.  It seems to be a problem within the Hyper-V guest OS.  

Question by:jjeldridge
    LVL 5

    Expert Comment

    Can you confirm on the OS side that you have a gigabit connection to the SAN?
     I've seen this sort of error occur on a server using a low-grade NIC that was starting to fail and could not maintain gigabit connectivity. It was replaced with a higher-grade server adapter and the problem disappeared.
    LVL 1

    Author Comment

    The server and NIC's are brand new (1 month).  All are gigabit.  2 NIC's are built-in HP nics and 2 are an external Intel Card.  The Intel NIC are teamed and go to the SAN.  The NIC's are presented as 10GB adapters in the GUEST and are running at 1 GB full duplex on the Host.

    The iSCSI initiator dropping only seems to happen during a backup operation.  We are using Backup exec 12.5 with a remote agent software on the Guest OS.  It also seems like the the iSCSI might be dropping when the backup is struggling to grab a file (not sure on this one but we are trying to confirm).  

    LVL 1

    Accepted Solution

    The issue has something to do with the NIC team.  We removed the NIC Team on the nic's running to the iSCSI SAN and we no longer see the issue.  The issue only seemed to arise after prolonged data transfer.  So a 1GB file transfered fine but trying to backup several hundred GB of data caused the drops.  

    We are still reviewing this for a more permanent resolution

    Expert Comment

    I have the same problem with win2008server and hp 2012i. I'll try to unteam the NICs later today.

    When copying data from the iscsi to another network device we get errors like:

    The description for Event ID 129 from source iScsiPrt cannot be found. Either the component that raises this event is not installed on your local computer or the installation is corrupted. You can install or repair the component on the local computer.

    If the event originated on another computer, the display information had to be saved with the event.

    The following information was included with the event:


    the message resource is present but the message is not found in the string/message table


    Initiator could not find a match for the initiator task tag in the received PDU. Dump data contains the entire iSCSI header.


    Connection to the target was lost. The initiator will attempt to retry the connection.
    LVL 13

    Expert Comment

    So has the perminent solution ever been found in terms of several hundered GB transfered and this occurs?
    initiator could not find a match for the initiator task tag in the received PDU.

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