Good day,

I have an HP 3PAR and RHEL 6.5 set up. When I run multipath -ll, I get the output below.

mpathe (360002ac0000000000000000f0000b429) dm-3 3PARdata,VV
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:3 sdm 8:192 active ready running
|- 3:0:0:3 sdl 8:176 active ready running
|- 2:0:0:3 sdj 8:144 active ready running
|- 4:0:1:3 sdbb 67:80 active ready running
`- 3:0:1:3 sdz 65:144 active ready running
mpathd (360002ac000000000000000100000b429) dm-2 3PARdata,VV
size=20G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:2 sdk 8:160 active ready running
|- 3:0:0:2 sdi 8:128 active ready running
|- 2:0:0:2 sdh 8:112 active ready running
|- 4:0:1:2 sdba 67:64 active ready running
`- 3:0:1:2 sdy 65:128 active ready running
mpathc (360002ac0000000000000000b0000b429) dm-0 3PARdata,VV
size=100G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:0 sdd 8:48 active ready running
|- 3:0:0:0 sdc 8:32 active ready running
|- 2:0:0:0 sdb 8:16 active ready running
`- 3:0:1:0 sdw 65:96 active ready running
mpathb (360002ac0000000000000000e0000b429) dm-1 3PARdata,VV
size=256G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:1 sdg 8:96 active ready running
|- 3:0:0:1 sdf 8:80 active ready running
|- 2:0:0:1 sde 8:64 active ready running
`- 3:0:1:1 sdx 65:112 active ready running
mpathh (360002ac0000000000000000d0000b429) dm-5 3PARdata,VV
size=2.0T features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:5 sds 65:32 active ready running
|- 3:0:0:5 sdq 65:0 active ready running
|- 2:0:0:5 sdr 65:16 active ready running
`- 4:0:1:5 sdbd 67:112 active ready running
mpathg (360002ac0000000000000000c0000b429) dm-6 3PARdata,VV
size=500G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:6 sdv 65:80 active ready running
|- 3:0:0:6 sdt 65:48 active ready running
|- 2:0:0:6 sdu 65:64 active ready running
`- 4:0:1:6 sdbe 67:128 active ready running
mpathf (360002ac000000000000000110000b429) dm-4 3PARdata,VV
size=768G features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 1:0:0:4 sdp 8:240 active ready running
|- 3:0:0:4 sdo 8:224 active ready running
|- 2:0:0:4 sdn 8:208 active ready running
`- 4:0:1:4 sdbc 67:96 active ready running

But under /dev/mapper/ I see the following items:

[root@bdoulxp468 mapper]# ls -lart
total 0
crw-rw----. 1 root root 10, 58 Aug 23 10:11 control
drwxr-xr-x. 2 root root 340 Aug 23 10:11 .
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathc -> ../dm-0
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathb -> ../dm-1
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathd -> ../dm-2
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathbp1 -> ../dm-8
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathe -> ../dm-3
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathdp1 -> ../dm-9
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathf -> ../dm-4
lrwxrwxrwx. 1 root root 8 Aug 24 13:16 mpathep1 -> ../dm-11
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathh -> ../dm-5
lrwxrwxrwx. 1 root root 8 Aug 24 13:16 mpathfp1 -> ../dm-10
lrwxrwxrwx. 1 root root 7 Aug 24 13:16 mpathg -> ../dm-6
lrwxrwxrwx. 1 root root 8 Aug 24 13:16 mpathhp1 -> ../dm-12
lrwxrwxrwx. 1 root root 8 Aug 24 13:16 mpathgp1 -> ../dm-13
drwxr-xr-x. 18 root root 7840 Aug 25 09:51 ..
lrwxrwxrwx. 1 root root 7 Aug 25 10:00 mpathcp1 -> ../dm-7

My question is, what is the difference between mpathc and mpathcp1, mpathg and mpathgp1, and so on.

When I try to kpartx -a /dev/mapper/mpathc, I get a device is busy error. I dont get any error when I run kpartx -a /dev/mapper/mpathcp1.

Thanks for your answers.

mpathc is the device, and mpathcp1 is the first partition. It's just like /dev/sda vs. /dev/sda1, only with mpath devices, the partition number is preceded by a 'p'.

The device busy error would suggest that mpathc was in use (e.g., /dev/mapper/mpathcp1 is mounted or part of a LVM volume group, etc.). Running kpartx on mpathcp1 wouldn't do anything, since that is a partition.

Thanks for the response. So is it safe to format mpathcp1 without running kpartx? I'm new to this and I'm just following the online guides I found through google.

Assuming by format, you mean put a file system onto mpathcp1, then yes. It can be used like any other partition - you do a mkfs and mount it, add it to an LVM group, etc.

Because you got a device busy, you should double-check it's not already being used. If you do a 'blkid /dev/mapper/mpathcp1', it will tell you if it's already configured for use. If it's in use, blkid will give you the UUID and TYPE (e.g. file system type, LVM, LUKS, etc.).

1 members found this post helpful.

Im having another problem. I edited some of the virtual volumes to correct the sizing, but now I see this under /dev/mapper
[root@bdoulxp468 mapper]# ls -lart
total 0
crw-rw----. 1 root root 10, 58 Sep 20 11:08 control
lrwxrwxrwx. 1 root root 7 Sep 20 16:10 mpathi -> ../dm-0
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathb -> ../dm-1
drwxr-xr-x. 18 root root 8320 Sep 20 16:11 ..
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathbp1 -> ../dm-9
drwxr-xr-x. 2 root root 340 Sep 20 16:11 .
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathd -> ../dm-2
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathe -> ../dm-3
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathdp1 -> ../dm-8
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathh -> ../dm-4
lrwxrwxrwx. 1 root root 8 Sep 20 16:11 mpathep1 -> ../dm-11
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathg -> ../dm-5
lrwxrwxrwx. 1 root root 8 Sep 20 16:11 mpathhp1 -> ../dm-12
lrwxrwxrwx. 1 root root 8 Sep 20 16:11 mpathgp1 -> ../dm-13
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathj -> ../dm-6
lrwxrwxrwx. 1 root root 7 Sep 20 16:11 mpathk -> ../dm-7
lrwxrwxrwx. 1 root root 8 Sep 20 16:11 mpathl -> ../dm-10

Did I miss a command to make mpathj mpathk mpathl have p1?

To get the p1, you need to partition the LUN.

1 members found this post helpful.

Partition from the 3par side or the OS side. Sorry for the dumb question. Thanks!

You can partition it on the OS side. The /dev/mapper/mpathX device can be treated like any other disk. You partition it the same, and use the partitions the same.

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Thank you so much! It works! I ran kpartx to map it. Then formatted and mounted it.