[rhelv6-list] Antwort: Re: MD devices lost after boot

[Roth, Sandro]

Hi all

I’ve worked through this with RedHat Support and they have come to the following solution.

In order to automatically assemble MD devices after a reboot, you will need to:


-       Create partitions on mpath devices with type fd – raid auto detect

-       Remove rd_NO_MD and rd_NO_DM from the grub kernel line

-       Edit the /etc/mdadm.conf DEVICE line to ‘partitions’ instead of ‘DEVICE /dev/…’

-       Run dracut –f

From the manpage:
              The  word  partitions  will  cause mdadm to read /proc/partitions and include all
              devices and partitions  found  therein.   mdadm  does  not  use  the  names  from
              /proc/partitions  but  only the major and minor device numbers.  It scans /dev to
              find the name that matches the numbers.

No init scripts or any other fiddling needed anymore ☺

There will also be a new KB article so keep an eye out for that one.


Cheers
Sandro

From: rhelv6-list-bounces at redhat.com [mailto:rhelv6-list-bounces at redhat.com] On Behalf Of Roth, Sandro
Sent: Donnerstag, 27. September 2012 03:59
To: Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list
Subject: Re: [rhelv6-list] Antwort: Re: MD devices lost after boot

I tried that as well, but still not assembling after a reboot.

And I think you’ll run into problems when you want to resize the LUN or partition in your case.
The kernel won’t update it’s partition table, you’d have to reboot.
At least that’s my experience. I might be wrong..

From: rhelv6-list-bounces at redhat.com<mailto:rhelv6-list-bounces at redhat.com> [mailto:rhelv6-list-bounces at redhat.com]<mailto:[mailto:rhelv6-list-bounces at redhat.com]> On Behalf Of Brian Long
Sent: Donnerstag, 27. September 2012 02:05
To: Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list
Subject: Re: [rhelv6-list] Antwort: Re: MD devices lost after boot

On Sep 27, 2012, at 7:49 AM, Andreas Reschke wrote:

rhelv6-list-bounces at redhat.com<mailto:rhelv6-list-bounces at redhat.com> schrieb am 27.09.2012 13:37:29:

> Brian Long <brilong at cisco.com<mailto:brilong at cisco.com>>
> Gesendet von: rhelv6-list-bounces at redhat.com<mailto:rhelv6-list-bounces at redhat.com>
>
> 27.09.2012 13:39
>
> Bitte antworten an
> "Red Hat Enterprise Linux 6 \(Santiago\) discussion mailing-list"
> <rhelv6-list at redhat.com<mailto:rhelv6-list at redhat.com>>
>
> An
>
> "Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list"
> <rhelv6-list at redhat.com<mailto:rhelv6-list at redhat.com>>
>
> Kopie
>
> Thema
>
> Re: [rhelv6-list] MD devices lost after boot
>
> On Sep 27, 2012, at 3:05 AM, Roth, Sandro wrote:
>
> Hi experts
>
> I wasn’t sure where to post this so I’m sending it to this list.
>
> We have a setup which uses lvm over md over multipath devices. (at
> least that’s the plan)
> According to this article it is supported in RHEL6 (it wasn’t in RHEL5)
> https://access.redhat.com/knowledge/solutions/48634
>
> I created my md device as follows
> # mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/
> mapper/mpatha /dev/mapper/mpathb
>
> Do /dev/mapper/mpatha and mpathb have partition type of "fd - Linux
> RAID auto"?  If not, they won't be set up properly when booting the server.
>
> /Brian/_______________________________________________
> rhelv6-list mailing list
> rhelv6-list at redhat.com<mailto:rhelv6-list at redhat.com>
> https://www.redhat.com/mailman/listinfo/rhelv6-list

Hi Brian,

sorry you're not right. There is no need for partitions with lvm. You can use the whole disk without partitions.

Something is broken with your email client since it's not maintaining threads properly (and it's prepending "Antwort:").

Last I knew, if you didn't use partitions with MD and/or LVM, certain things wouldn't work properly.  I always create a single whole-disk partition and give it a "fd" type.  I think this is still the best practice although it's not a requirement.

/Brian/

--
       Brian Long                             |       |
       Corporate Security Programs Org    . | | | . | | | .
                                              '       '
                                              C I S C O

This email message and any attachments are confidential and may be privileged. If you are not the intended recipient, please notify us immediately and destroy the original transmittal. You are hereby notified that any review, copying or distribution of it is strictly prohibited. Thank you for your cooperation.



Header information contained in E-mails to and from the company are monitored for operational reasons in accordance with swiss data protection act.



This email message and any attachments are confidential and may be privileged. If you are not the intended recipient, please notify us immediately and destroy the original transmittal. You are hereby notified that any review, copying or distribution of it is strictly prohibited. Thank you for your cooperation.

Header information contained in E-mails to and from the company are monitored for operational reasons in accordance with swiss data protection act.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/rhelv6-list/attachments/20121015/e5652c79/attachment.htm>