topic Re: Multipath in Operating System - Linux

Multipath

tarek_3 — Wed, 10 Jan 2007 07:04:47 GMT

Hi.

We have a MS500 G2 storage attached to a DL380 using two Smart Array 642 SCSI running Red Hat Enterprise Server 4.

We have 1 LUN and this LUN has two paths in Linux:
/dev/cciss/c1d0
/dev/cciss/c2d0

When we tried to enable Multipath with mdadm mannualy, it works, but we cannot do this change persistent on boot.

Add /dev/md0 with command:
mdadm -C /dev/md0 -l multipath -n 2 /dev/cciss/c1d0p1 /dev/cciss/c2d0p1
WORK.

Reboot the system - doesn't work, and this message appears:
mdadm: failed to add /dev/cciss/c1d0p1 to /dev/md0: Device or resource busy
mdadm: /dev/md0 has been started with 2 drives and -1 spares.

Please, help me.

Re: Multipath

Jerome Henry — Wed, 10 Jan 2007 11:35:49 GMT

Hi hassoun,

Do you have /boot on /dev/md0 ?

J

Re: Multipath

cristian mazza — Fri, 12 Jan 2007 03:43:05 GMT

you must set the partition to type fd "linux auto raid" in this way the boot process discover the partitions and assign it to md device.

also, you can modify the file/etc/mdadm.conf to insert the md device and the phisical disk.

regards, Cristian

Re: Multipath

Natasha3 — Tue, 07 Nov 2023 08:16:34 GMT

I have a server having two hdds (/dev/sdc and /dev/sdd) . Both hdds are same physical disk sent by two different paths to the sever. I am trying to create a multipath raid device using the following command :
"mdadm --create /dev/md0 --level=multipath --raid-devices=2 /dev/sdd /dev/sdc "
But facing error
" mdadm: RUN_ARRAY failed: Invalid argument "

my /etc/mdadm.conf file
DEVICE /dev/sdd /dev/sdc
ARRAY /dev/md0 metadata=1.2 name=myarray:0 UUID=261fb9c:976d0d97:30bc63ce:85e76e91

Can anyone help me with this?

Re: Multipath

Sunitha_Mod — Thu, 09 Nov 2023 07:59:52 GMT

Hello @Natasha3,

Thank you for posting!

Since you have posted in an old topic and there is no response yet, we would recommend you create a new topic using the create "New Discussion" button, so the experts can check and assist you further.