I was trying to create the device file partition but I was receiving an error message

root@linux:~ # kpartx -a /dev/mapper/mpathm
device-mapper: create ioctl failed: Device or resource busy
create/reload failed on mpathm1

The disk already had a partition. Let’s use dmsetup to see what we have

root@linux:~ # dmsetup ls | grep mpathm
mpathm-part1 (253, 38)
mpathm (253, 32)

We already have a mpathm partition registered so we need to remove

root@linux:~ # dmsetup remove mpathm-part1

Then retry

root@linux:~ # kpartx -a /dev/mapper/mpathm
root@linux:~ #

• Linux