RH: Resizing LUN using multipath

Sometimes it is needed to resize ( let’s say increase ) the size of a LUN on Linux.

It is possible to do it all online ( but not without risc :-/ )

What you need to do is the follwoing :

# multipath -ll
360a980006467662d435a687a52734550 dm-13 NETAPP,LUN
\_ round-robin 0 [prio=16][active]
\_ 1:0:0:5 sdf 8:80 [active][ready]
\_ 1:0:1:5 sdl 8:176 [active][ready]
\_ 2:0:0:5 sdr 65:16 [active][ready]
\_ 2:0:1:5 sdx 65:112 [active][ready]
\_ round-robin 0 [prio=2][enabled]
\_ 2:0:2:5 sdad 65:208 [active][ready]
\_ 2:0:3:5 sdaj 66:48 [active][ready]

For all devices attached to the specified LUN

# for DEVICES in `multipath -ll 360a980006467662d435a687a52734550 | grep “_ [0-9]” | awk ‘{print $3}’`
blockdev –rereadpt /dev/${DEVICES}

Now start multipathd in interactive mode

# multipathd -k

multipathd> list multipaths

name sysfs uuid
360a980006467662d435a687a52734550 dm-13 360a980006467662d435a687a52734550

multipathd> resize multipath dm-13

Now resize the LVM Physical Volume

# pvresize /dev/dm-13>
Physical volume “/dev/dm-13>” changed
1 physical volume(s) resized / 0 physical volume(s) not resized

Now you can see the increased size with vgs and resize the Logical Volume.

Don’t forget to do a resize2fs after resizing the Logical Volume

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