Resizing Online Mulripath Disk in Linux

Here is the steps to Resize an Online Multipath Disk which is using Linux native device mapper as multipath solution.


1. Resize your physical disk in SAN. SAN Admins will do this. 
2. Use the following command to find the paths to the LUN:

# multipath -l

3. Now, Resize your paths. For SCSI devices, use the following command:

# echo 1 > /sys/block/<device_name>/device/rescan

4. Resize your multipath device by running the multipathd resize command:

# multipathd -k'resize map mpath0'

5. Resize the  File System (Assuming LVM is NOT used)

# resize2fs /dev/mapper/mpath0

If LVM is used, you need to do the following:

#pvscan

Check your Disk Changes detected under LVM:

#pvs or pvdisplay 

#vgscan

To check the VG Size is Increased:

#vgs or vgdisplay

Now Extend the LV: 

#lvextend -L +<SIZE_TO_BE_INCREASED>G <LV_NAME>

Finally Extend the File System

#resize2fs <LV_NAME>

Thats all. You are done