One of the issues that I have run into in the past when working with iscsi disks occurs when a host (initiator) is unable to logout gracefully from an iscsi disk when attempting to shutdown or reboot a host. Note that this is a known issue and is documented here and here. I have not read completely through the RHEL 6 Bugzilla to see if the issue has been resolved, however I can tell you that I have seen this issue in RHEL 6.2.
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RHEL6 – Accessing ISCSI Disks with Iscsiadm
ISCSI is scsi (Small Computer System Interface) over IP. Where SCSI is the protocol and IP is the transport mechanism. This is going to be a quick and dirty overview of how to login to and mount an iscsi disk. This will not be an overview of how to share out a disk via iscsi. … Continue reading RHEL6 – Accessing ISCSI Disks with Iscsiadm