System information
Note
You can also re-scan iSCSI logical units using the following command:
# iscsiadm -m node -R -I interface
Replace interface with the corresponding interface name of the resized logical unit (for
example, i face0 ). This command performs two operations:
It scans for new devices in the same way that the command echo "- - -" >
/sys/cl ass/scsi _ho st/host/scan does (refer to Section 25.12, “ Scanning iSCSI
Interconnects” ).
It re-scans for new/modified logical units the same way that the command echo 1 >
/sys/bl o ck/sd X/d evi ce/rescan does. Note that this command is the same one used
for re-scanning fibre-channel logical units.
25.14 .3. Updat ing t he Siz e of Your Mult ipat h Device
If multipathing is enabled on your system, you will also need to reflect the change in logical unit size
to the logical unit's corresponding multipath device (after resizing the logical unit). For Red Hat
Enterprise Linux 5.3 (or later), you can do this through mul ti pathd . To do so, first ensure that
mul ti pathd is running using servi ce mul ti pathd status. Once you've verified that
mul ti pathd is operational, run the following command:
# multipathd -k"resize map multipath_device"
The multipath_device variable is the corresponding multipath entry of your device in
/d ev/mapper. Depending on how multipathing is set up on your system, multipath_device can
be either of two formats:
mpathX, where X is the corresponding entry of your device (for example, mpath0 )
a WWID ; for example, 36 0 0 50 8b4 0 010 5e210 0 0 0 9 0 0 00 0 4 90 0 0 0
To determine which multipath entry corresponds to your resized logical unit, run mul ti path -l l .
This displays a list of all existing multipath entries in the system, along with the major and minor
numbers of their corresponding devices.
Important
Do not use mul ti pathd -k"resi ze map multipath_device" if there are any commands
queued to multipath_device. That is, do not use this command when the no _path_retry
parameter (in /etc/mul ti path. co nf) is set to "q ueue", and there are no active paths to
the device.
If your system is using Red Hat Enterprise Linux 5.0-5.2, you will need to perform the following
procedure to instruct the mul ti pathd daemon to recognize (and adjust to) the changes you made
to the resized logical unit:
Pro ced u re 25.6 . Resiz in g t h e Co rresp o n d in g Mu lt ip at h Device ( R equired fo r Red Hat
En t erp rise Lin u x 5.0 - 5.2)
Chapt er 2 5. O nline St orag e Manag ement
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