Configure persistent names in multipath

It is recommended that such systems have persistent device names configured for their hosts. This helps with live migration as well as providing consistent device names and storage for multiple virtualized systems.

Universally Unique Identifiers (UUIDs) are a standardized method for identifying computers and devices in distributed computing environments. This section uses UUIDs to identify the iSCSI or Fiber Channel LUN. UUIDs persist after device reboot, disconnection, and swapping. The UUID is similar to a label on the device.

We are going to see two ways on how to change the name of the disk in order to quickly identify it:

First option:

using the command multipath -ll we check the UUID from the disk:

text

multipath -ll

mpatha (3624a93708731da97f48571620001105a) dm-6 PURE ,FlashArray

size=232G features=’0′ hwhandler=’0′ wp=rw

`-+- policy=’service-time 0′ prio=1 status=active

|- 3:0:0:10 sdb 8:16 active ready running

|- 4:0:0:10 sdc 8:32 active ready running

|- 5:0:0:10 sdd 8:48 active ready running

|- 6:0:0:10 sde 8:64 active ready running

|- 7:0:0:10 sdf 8:80 active ready running

|- 10:0:0:10 sdh 8:112 active ready running

|- 8:0:0:10 sdg 8:96 active ready running

`- 9:0:0:10 sdi 8:128 active ready running

Now we only have to add the configuration and restart the service. multipathd

Bash

cat /etc/multipath.conf
multipaths {

multipath {

wwid «3624a93708731da97f48571620001105a»

alias volmysql

}

}

We restart the service.

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/etc/init.d/multipathd restart

Second option:

This option is a little more tacky, we won't deny it... but effective.

using the command multipath -ll we check the UUID from the disk:

text

multipath -ll

mpatha (3624a93708731da97f48571620001105a) dm-6 PURE ,FlashArray

size=232G features=’0′ hwhandler=’0′ wp=rw

`-+- policy=’service-time 0′ prio=1 status=active

|- 3:0:0:10 sdb 8:16 active ready running

|- 4:0:0:10 sdc 8:32 active ready running

|- 5:0:0:10 sdd 8:48 active ready running

|- 6:0:0:10 sde 8:64 active ready running

|- 7:0:0:10 sdf 8:80 active ready running

|- 10:0:0:10 sdh 8:112 active ready running

|- 8:0:0:10 sdg 8:96 active ready running

`- 9:0:0:10 sdi 8:128 active ready running

Once identified the UUID of the volume which we want to change the name to access the file: /etc/multipath/bindings

We modify the current name (mpatha) for whoever we want.

Bash

cat /etc/multipath/bindings
# Multipath bindings, Version : 1.0

# NOTE: this file is automatically maintained by the multipath program.

# You should not need to edit this file in normal circumstances.

#

# Format:

# alias wwid

#

mpatha 3624a93708731da97f485716200011073

Example:

text

volmysql  3624a93708731da97f485716200011073

After modifying the file, remove all multipath devices and restart the service.

text

multipath -F

multipath -r

:wq!

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