System information

Remote Port
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Remote Port
fast_i o _fa
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X X
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Host po rt_i d X X X X X
Host
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X X X
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25.2. iSCSI
This section describes the iSCSI API and the i scsi ad m utility. Before using the i scsi ad m utility,
install the i scsi -i ni ti ato r-uti ls package first by running yum i nstal l i scsi -
i ni ti ato r-uti l s.
In Red Hat Enterprise Linux 6, the iSCSI service is lazily started by default. If root is not on an iSCSI
device or there are no nodes marked with no d e. startup = auto mati c then the iSCSI service will
not start until an i scsi ad m command is run that requires iscsid or the iscsi kernel modules to be
started. For example, running the discovery command i scsi ad m -m d i sco very -t st -p
i p: po rt will cause iscsiadmin to start the iSCSI service.
To force the iscsid daemon to run and iSCSI kernel modules to load, run servi ce i scsi d
fo rce-start.
Note
When using the hal daemon with a large number of iSCSI LUNs, over several thousand, the --
chi l d -ti meo ut option should be used in order to avoid boot failures. The --chi l d -
ti meo ut option sets the number of seconds to wait for all disk probes to run. For example, to
force the hal daemon to wait 10 minutes and 30 seconds, the option would read --chi l d-
ti meo ut= 630 . The default time is 250 seconds. While this means the hal daemon will take
longer to start, it will give enough time for all disk devices to be recognized and avoid boot
failures.
The reason for this work around is because in 2003 when the hal daemon was created, it was
unusual to have more than a dozen iSCSI disks. It is for this reason, the hal daemon has been
removed in Red Hat Enterprise Linux 7 and replaced with udisks.
For more information refer to the knowledgebase article located at
https://access.redhat.com/solutions/27571.
25.2.1. iSCSI API
To get information about running sessions, run:
# iscsiadm -m session -P 3
[a] [b ]
[a] Sup p o rted as o f Red Hat Enterp rise Linux 5.4
[b ] Sup p o rted as o f Red Hat Enterp rise Linux 6 .0
Red Hat Ent erprise Lin ux 6 St orage Admin ist rat io n G uide
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