NEC Express5800 Series Maintenance Manual page 148

Chapter 2 Configuring and Upgrading the System

Configuring multi path
1. Run the following command to start path watch daemon(multipathd).
# systemctl start multipathd
# systemctl enable multipathd
2. Run the following command to create multipath device.
# multipath
After executing this command, the dm device of dm-X (X indicating the number) is created under /dev
while the dm-mp device (symbolic link to the dm device) of mpathN and mpathNM (N indicating an
alphabetical character, M indicating the number 1 or more) is created under /dev/mapper. mpathN is Nth
LUN, mpathNM is Mth partition in mpathN.
3. Run the following command to check the path condition. The path condition of each dm-mp device can
be displayed. Check that there is no failed or faulty path.
# multipath -ll
4. Create the partition and file system, and mount them. The dm device is internally used by Linux. Be sure
to use the dm-mp device. Also adding the LUN entry to /etc/fstab, use the dm-mp device name. The
server must be restarted to reflect the change in the partition to the system.

Procedures for changing the LUN allocation to the ft server (important)
When allocating the LUN on iStorage to the ft server, or clearing the allocation, be sure to follow either of the
procedure A or procedure B described below. Otherwise, the ft server may not be duplicated.
Procedure A at the local site
When the server starts up first after change of the LUN allocation, the following message is output to
the local console of the ft server, and input may be prompted.
Comparing initramfs and rootfs storage config...
Missing or stale /etc/multipath/wwids in initramfs!
Missing or stale /etc/multipath/bindings in initramfs!
*** Syncronize these files by regenerating the initramfs? [Y/n]
If this screen appears, input [Y].
Then, the following screen appears. Input [Y] again. The server restarts.
Regenerating initramfs.
This may take a few minutes...
[REPAIR] prep_20-multipath
Done.
*** System reboot required to complete repair, reboot now [Y/n]
The description of the required work is completed here.
If the message to prompt you to input as shown above does not appear, there is no required work
anymore.
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Important This operation must be executed by only root user.
Express5800/R320e-E4, R320e-M4 Maintenance Guide (Linux)
5. Installing and Replacing Optional Devices