multipath issue

robertjinx · 10-10-2015, 11:17 AM

Hmm, very strange, can you also paste the output of the command:

Code:

cat /proc/partitions

You are right, the disks are not there, but I cant understand why, just that fdisk doesn't see them as disks. My issue also here is that in comment #10 you have 5 disks, but in comment #15 way more then that. Are you giving us the output from the same machine?

business_kid · 10-11-2015, 04:52 AM

Thank you for the fdisk -l output. The thing that leaps out at me is

Code:

Disk /dev/sdd doesn't contain a valid partition table
Disk /dev/sdb doesn't contain a valid partition table

That answers the problem raised in post #1. sdd has to be repartitioned, or go at it with testdisk.

All the other ones(sdf, sdg, sdh, sdi, sdk, sdl, sdm, sdn, sdp, &sdq) seem to be configured as one massive drive.

robertjinx · 10-12-2015, 01:15 AM

Quote:

Originally Posted by business_kid

Thank you for the fdisk -l output. The thing that leaps out at me is

Code:

Disk /dev/sdd doesn't contain a valid partition table
Disk /dev/sdb doesn't contain a valid partition table

That answers the problem raised in post #1. sdd has to be repartitioned, or go at it with testdisk.

All the other ones(sdf, sdg, sdh, sdi, sdk, sdl, sdm, sdn, sdp, &sdq) seem to be configured as one massive drive.

Yes, but when I search for them, they didn't pop out. The strange part is 'why don't they have partition?' as the other 2 drivers which are part of the same multipath device do.

business_kid · 10-12-2015, 12:08 PM

If you don't have partitions, you don't need a partition table. Common examples are usb boot images, which overwrite the partition table,

/dev/sda = disk
/dev/sda1 = a partition

If you have no partition table, you just address the disk.
cp -a <all my files> /dev/sda or whatever.

robertjinx · 10-12-2015, 01:11 PM

Quote:

Originally Posted by business_kid

If you don't have partitions, you don't need a partition table. Common examples are usb boot images, which overwrite the partition table,

/dev/sda = disk
/dev/sda1 = a partition

If you have no partition table, you just address the disk.
cp -a <all my files> /dev/sda or whatever.

I think you misread the results, the guy reported that /dev/sdc and /dev/sde are not visible in 'fdisk -l' output and the only visible ones are /dev/sdb and /dev/sdd. So 2 block devices of the multipath device are not visible in 'fdisk -l' which is not normal.

Not sure what does sda or anything else have to do with that?

voleg · 10-13-2015, 03:14 AM

You should no use /dev/sdXX when using multipath. You should use /dev/mapper/whatever.
I do not recommend you make partitions on external LUNs, use whole device (/dev/mapper/mpathXX)
as PV for creating VG. More of that, you have to fix "filter" in /etc/lvm/lvm.conf to mask all
not multipath devices, otherwise LVM can use any single path to work by mistake.

I have memo HOWTO LUNs on Linux using native tools. This example based on NetApp LUNs, however it good for EMC too.

asar2121 · 10-20-2015, 05:02 AM

Try restarting iscsi daemon and multipathd services in linux machine. Please post the outputs of below command and search for errors or warning in /var/log/messages. If you found anything related to this in /var/log/messages. Please post the same....

#lsblk
#multipath -ll