Consider the following scenario:

• You use Microsoft iSCSI Initiator to connect to an iSCSI target from a computer that is running Windows Vista or Windows Server 2008.
• An iSCSI Protocol Data Unit (PDU) is rejected by the target for one of the reasons that are outlined in section 10.17.1 of iSCSI Specification Request for Comment (RFC) 3720.

In this scenario, iSCSI Initiator should resend the PDU that was rejected by the iSCSI target. However, iSCSI Initiator may be unable to communicate with the iSCSI target for several minutes.

Specifically, iSCSI Initiator cannot communicate with the target for a period of five times the Disk Timeout value that is specified in the following registry entry:

Subkey: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Disk
Entry: TimeoutValue
Type: REG_DWORD
Value: The Disk Timeout Value in seconds

After a period of five times the Disk Timeout Value elapses, iSCSI Initiator performs session recovery, and then the iSCSI session is dropped and reestablished. Eventually, iSCSI Initiator may be able to communicate with the iSCSI target again.

Internet Small Computer System Interface: A network protocol standard that allows the use of the SCSI protocol over TCP/IP networks.

Consider the following scenario. On a Windows Vista-based computer, you start the Microsoft iSCSI Initiator service. Then, you log off an iSCSI target. In this scenario, the following event is written to the System log:

Log Name: System
Source: PlugPlayManager
Event ID: 12
Task Category: None
Level: Error
Keywords: Classic
Description: The device Device_Name (SCSI\Disk&Ven_EQLOGIC&Prod_100E-00\1&1c121344&0&000000) disappeared from the system without first being prepared for removal.

Note: This event occurs only if the target is an unformatted (RAW) volume.

A Warning event message that resembles the following may be logged in the Windows Vista event log:

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.
The message has no description.

This message is logged when the Vista initiator sends an iSCSI Task Management command to the target device, and the device (\Device\ScsiPort0) does not respond within the time-out period.