Linux Storage - mppUpdate and lsvdev

category: solutionz · date: 2010-09-30 · updated: 2026-10-03 · author: LALA

Linux Storage Solution · Config document · referenced from RDAC installation and operation

notemppUpdate -d DS5300-SITEB removes the standby array from the persistent mapping and rebuilds the initrd. It is one step of the fix in RDAC problems and LUN removal; run alone it leaves the array's .wwn file behind.

mppUpdate maintains the RDAC (MPP) driver's persistent mapping file /var/mpp/devicemapping and rebuilds the MPP initrd afterwards; without an option it only rebuilds the initrd, which is what a SaveSettings change through mppUtil -o needs. /opt/mpp/lsvdev prints the basic LUN mapping, array by array, to the sd device names the virtual adapter gave them.

Item	Value
Commands	`/usr/sbin/mppUpdate`, `/opt/mpp/lsvdev`
Run as	`root` on `mppsrv01`
Host	Red Hat Enterprise Linux AS 4, kernel `2.6.9-89.0.9.ELsmp`, two QLogic HBAs
Edits	`/var/mpp/devicemapping`, `/boot/mpp-2.6.9-89.0.9.ELsmp.img`
Arrays	`DS5300-SITEA` (`/dev/sda`, `/dev/sdb`), `DS5300-SITEB` (`/dev/sdc`, `/dev/sdd`)
Driver version	RDAC `09.03.0B05.0331`

The commands

The mppUpdate usage list as the notes keep it, without output:

bash

$ mppUpdate -d DS5300-SITEB
$ mppUpdate -c

Command	Task, as the notes word it
`mppUpdate -d DS5300-SITEB`	remove the disk array named `DS5300-SITEB` from the file `/var/mpp/devicemapping`
`mppUpdate -c`	clear every disk array entry out of `/var/mpp/devicemapping`
`mppUpdate`	rebuild the initrd (used after `mppUtil -o …,SaveSettings` and after removing a `.wwn` file; the notes list it only in those places)

The examples with output

Removing the standby array from the persistent mapping. The output confirms the removal, counts the QLogic ports and rebuilds the initrd:

bash

$ mppUpdate -d DS5300-SITEB

output 3 lines

The module DS5300-SITEB was removed from the MPP persistence mapping list (/var/mpp/devicemapping).
Detected 2 QLogic Host Adapter Port(s) on the system
Creating new MPP initrd image...

The basic LUN mapping, taken while both arrays were known:

bash

$ /opt/mpp/lsvdev

output 6 lines

Array Name      Lun    sd device
-------------------------------------
DS5300-SITEA    1     -> /dev/sda
DS5300-SITEA    2     -> /dev/sdb
DS5300-SITEB    1     -> /dev/sdc
DS5300-SITEB    2     -> /dev/sdd

Reading the outputs

Line	Reading
`The module DS5300-SITEB was removed from the MPP persistence mapping list`	the driver calls an array an "array module"; the line `1:DS5300-SITEB` is gone from `devicemapping`
`Detected 2 QLogic Host Adapter Port(s) on the system`	the two HBAs `host0` and `host1`; as I read it, the initrd is built with the drivers of the HBAs the tool finds
`Creating new MPP initrd image...`	the initrd `/boot/mpp-2.6.9-89.0.9.ELsmp.img` is written again, so the change survives the next boot
`DS5300-SITEA 1 -> /dev/sda`	LUN 1 of the main array is the system's `/dev/sda`: the virtual adapter's disks carry the plain `sd` names, and the four physical paths behind each have none, because `mppUpper` keeps the HBAs from publishing them
`DS5300-SITEB 1 -> /dev/sdc`	the standby array's LUNs are `sdc` and `sdd`, the same names `mppBusRescan` printed when it found them (`2:0:1:1->/dev/sdc`, `2:0:1:2->/dev/sdd`)

The disk names are a reminder of why problem 1 matters: sdc and sdd are a mirror of sda and sdb, so anything that identifies disks by content (an LVM physical volume label, for instance) sees each twice. The -d output is repeated in Removing the standby array from RDAC, where it is the second step of the fix.

Checked against NetApp SANtricity 12.10

As built	Today
`mppUpdate` after a change to `/etc/mpp.conf` or `/var/mpp/devicemapping`	The readme of this build: "If you make any changes to MPP configuration file (/etc/mpp.conf) or persistent binding file (/var/mpp/devicemapping), please run mppUpdate to re-build RAMdisk image"
`/opt/mpp/lsvdev` for the LUN mapping	Still described at the same path in the SANtricity 11.20 Multipath Drivers Guide (2015), which already called RDAC not recommended and to be deprecated; RDAC was discontinued with SANtricity OS 11.25
RDAC's persistent mapping and initrd	Gone with the driver, discontinued with SANtricity OS 11.25. With DM-Multipath the kernel attaches `scsi_dh_rdac` to `IBM 1818` devices by itself, and the mapping of paths to one device is shown by `multipath -ll`