mdadm.conf

[Javier Perez]

Hi.
I just built an Raid 1 for /  , /boot and /boot/efi using the blivet tool
during installation.
Everything works fine so far, but I noticed that the Array lines on
mdadm.conf look funny

====mdadm.conf====
 mdadm.conf written out by anaconda
MAILADDR root
AUTO +imsm +1.x -all
ARRAY /dev/md/Fedora_efi level=raid1 num-devices=2
UUID=e82eff07:23f7fa9f:f3d9814a:f9b7ef81
ARRAY /dev/md/boot level=raid1 num-devices=2
UUID=ffc4f8f2:9dc1b2de:1bce2836:d1968df7\
========end==========
It does not have the full UUIDs of the partitions, only the last  8
characters.

It caught me by surprise because the mdadm.conf man page says nothing
about it.

[Roger Heflin]

Did you build a mdadm raid1 or a dm-raid raid 1?

+imsm means you built a dm-raid device (software raid that the
bios/efi is aware of) and it is slightly different from a normal
mdadm.

If it works and uses the correct device names on each boot up then I
would not touch it.

If you do touch it then you will need to rebuild the initramfs as that
file will be in the initramfs so that it can start up the raid to boot
the node.

On Tue, Jul 2, 2024 at 10:30 AM Javier Perez  wrote:
> Hi.
> I just built an Raid 1 for /  , /boot and /boot/efi using the blivet tool during installation.
> Everything works fine so far, but I noticed that the Array lines on mdadm.conf look funny
>
> ====mdadm.conf====
>  mdadm.conf written out by anaconda
> MAILADDR root
> AUTO +imsm +1.x -all
> ARRAY /dev/md/Fedora_efi level=raid1 num-devices=2 UUID=e82eff07:23f7fa9f:f3d9814a:f9b7ef81
> ARRAY /dev/md/boot level=raid1 num-devices=2 UUID=ffc4f8f2:9dc1b2de:1bce2836:d1968df7\
> ========end==========
> It does not have the full UUIDs of the partitions, only the last  8 characters.
>
> It caught me by surprise because the mdadm.conf man page says nothing about it.
> --
>
> /_/\
>  |O O|  [e-mail]
> ~~~~          While the night runs
> ~~~~          toward the day...
>  m m       Pepebuho watches
>                from his high perch.
> --
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[Javier Perez]

Hmmmm
Did not know there was such a thing as dm-raid. It was built up by the
installer.
Makes me wonder, should something happen to the MB, will it be problematic
to move the discs to another system?
I am assuming if one disk falls, the mdmraid commands to rebuild the array
would still be the same

On Tue, Jul 2, 2024, 11:15 Roger Heflin  wrote:
> Did you build a mdadm raid1 or a dm-raid raid 1?
>
> +imsm means you built a dm-raid device (software raid that the
> bios/efi is aware of) and it is slightly different from a normal
> mdadm.
>
> If it works and uses the correct device names on each boot up then I
> would not touch it.
>
> If you do touch it then you will need to rebuild the initramfs as that
> file will be in the initramfs so that it can start up the raid to boot
> the node.
>
> On Tue, Jul 2, 2024 at 10:30 AM Javier Perez  wrote:
> > Hi.
> > I just built an Raid 1 for /  , /boot and /boot/efi using the blivet
>
> tool during installation.
> > Everything works fine so far, but I noticed that the Array lines on
>
> mdadm.conf look funny
> > ====mdadm.conf====
> >  mdadm.conf written out by anaconda
> > MAILADDR root
> > AUTO +imsm +1.x -all
> > ARRAY /dev/md/Fedora_efi level=raid1 num-devices=2
>
> UUID=e82eff07:23f7fa9f:f3d9814a:f9b7ef81
> > ARRAY /dev/md/boot level=raid1 num-devices=2
>
> UUID=ffc4f8f2:9dc1b2de:1bce2836:d1968df7\
> > ========end==========
> > It does not have the full UUIDs of the partitions, only the last  8
>
> characters.
> > It caught me by surprise because the mdadm.conf man page says nothing
>
> about it.
> > --
> >
> > /_/\
> >  |O O|  [e-mail]
> > ~~~~          While the night runs
> > ~~~~          toward the day...
> >  m m       Pepebuho watches
> >                from his high perch.
> > --
> > _______________________________________________
> > users mailing list -- [e-mail]
> > To unsubscribe send an email to [e-mail]
> > Fedora Code of Conduct:
>
> https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> > List Archives:
>
> https://lists.fedoraproject.org/archives/list/[e-mail]
> > Do not reply to spam, report it:
> https://pagure.io/fedora-infrastructure/new_issue
>
> users mailing list -- [e-mail]
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[Roger Heflin]

I believe to move to another motherboard you would need to do a bit of
messing around.  If the new motherboard was the same vendor and was
also set the same (assuming it is set to raid for SATA) then it would
likely work.

You might want to check in the bios/firmware/EFI to see what the SATA
controller is set to.   Typically you have at least raid and ahci and
this is used when it is set to raid and would need work to move to
another motherboard.   If you change it to ahci it will stop booting
without some serious adjustments.

I assume the mdadm commands should be similar though but even if they
aren't there should be documentation on how it differs.   I avoid the
raid setting on the motherboard because of MB swap limitations.

On Tue, Jul 2, 2024 at 4:16 PM Javier Perez  wrote:
> Hmmmm
> Did not know there was such a thing as dm-raid. It was built up by the installer.
> Makes me wonder, should something happen to the MB, will it be problematic to move the discs to another system?
> I am assuming if one disk falls, the mdmraid commands to rebuild the array would still be the same
>
> On Tue, Jul 2, 2024, 11:15 Roger Heflin  wrote:
> > Did you build a mdadm raid1 or a dm-raid raid 1?
> >
> > +imsm means you built a dm-raid device (software raid that the
> > bios/efi is aware of) and it is slightly different from a normal
> > mdadm.
> >
> > If it works and uses the correct device names on each boot up then I
> > would not touch it.
> >
> > If you do touch it then you will need to rebuild the initramfs as that
> > file will be in the initramfs so that it can start up the raid to boot
> > the node.
> >
> > On Tue, Jul 2, 2024 at 10:30 AM Javier Perez  wrote:
> > > Hi.
> > > I just built an Raid 1 for /  , /boot and /boot/efi using the blivet tool during installation.
> > > Everything works fine so far, but I noticed that the Array lines on mdadm.conf look funny
> > >
> > > ====mdadm.conf====
> > >  mdadm.conf written out by anaconda
> > > MAILADDR root
> > > AUTO +imsm +1.x -all
> > > ARRAY /dev/md/Fedora_efi level=raid1 num-devices=2 UUID=e82eff07:23f7fa9f:f3d9814a:f9b7ef81
> > > ARRAY /dev/md/boot level=raid1 num-devices=2 UUID=ffc4f8f2:9dc1b2de:1bce2836:d1968df7\
> > > ========end==========
> > > It does not have the full UUIDs of the partitions, only the last  8 characters.
> > >
> > > It caught me by surprise because the mdadm.conf man page says nothing about it.
> > > --
> > >
> > > /_/\
> > >  |O O|  [e-mail]
> > > ~~~~          While the night runs
> > > ~~~~          toward the day...
> > >  m m       Pepebuho watches
> > >                from his high perch.
> > > --
> > > _______________________________________________
> > > users mailing list -- [e-mail]
> > > To unsubscribe send an email to [e-mail]
> > > Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> > > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> > > List Archives: https://lists.fedoraproject.org/archives/list/[e-mail]
> > > Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
> >
> > --
> > _______________________________________________
> > users mailing list -- [e-mail]
> > To unsubscribe send an email to [e-mail]
> > Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> > List Archives: https://lists.fedoraproject.org/archives/list/[e-mail]
> > Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
>
> --
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