/boot/efi partitions on software RAID1

General support questions
kenn
Posts: 17
Joined: 2014/07/06 09:25:44

/boot/efi partitions on software RAID1

Post by kenn » 2014/07/07 10:06:23

Hello! I have a problem on installing CentOS 6.5 in Software RAID1 system.
I want to set up software RAID1 on two SATA HDD.
When I have installed CentOS, I have warned from installer
"You have not created a /boot/efi partition."
nevertheless I have created a /boot/efi partition in a /dev/md0 (RAID1 drive).

What I wonder is when I create a /boot/efi partition as a normal partition(non RAID)
"EFI System Partition" can be selected as a format type.
On the other hand, for md0(RAID1), the "EFI System Partition" item is disappeared
and cannot be selected.
(So I chose other formats, vfat and ext4.)
(nether of them working.)

In my understand, boot partition can be placed on RAID1 drive.

How can I install /boot/efi on RAID1 drive?
Please guide me.
Thank you.

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Super Jamie
Posts: 310
Joined: 2014/01/10 23:44:51

Re: /boot/efi partitions on software RAID1

Post by Super Jamie » 2014/07/07 10:16:35

kenn wrote:I have created a /boot/efi partition in a /dev/md0 (RAID1 drive)
You can't do this. The EFI specification mandates that the firmware recognise a FAT32 partition as the EFI System Partition. The firmware cannot recognise Linux Software RAID as an EFI System Partition.

The correct way is to install your /boot and / and other filesystems on software RAID, and to duplicate the FAT32 partition in sda1 onto sdb1, then create another EFI firmware boot menu entry pointing to the backup partition.

kenn
Posts: 17
Joined: 2014/07/06 09:25:44

Re: /boot/efi partitions on software RAID1

Post by kenn » 2014/07/07 10:55:38

Thank you for your quick response.

I have tried what you said, but still have a trouble.
/boot and / and other filesystems on software RAID
I made two RAID drives, md0 for /boot, md1 for /
Then installer still warn
"You have not created a /boot/efi partition."

Should I have to make a partition /boot/efi separately?
And if so, on which drive(sda or sdb) should I make a partition?

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Super Jamie
Posts: 310
Joined: 2014/01/10 23:44:51

Re: /boot/efi partitions on software RAID1

Post by Super Jamie » 2014/07/07 11:02:07

kenn wrote:Should I have to make a partition /boot/efi separately?
And if so, on which drive(sda or sdb) should I make a partition?
Yes, that's right, you need to have something like:

sda (first drive)
- sda1 - FAT32 - /boot/efi - in firmware boot menu as "CentOS"
- sda2 - Linux software RAID - /boot
- sda3 - Linux software RAID - /

sdb (second drive)
- sdb1 - FAT32 - copy of /boot/efi - in firmware boot menu as "CentOS Backup"
- sdb2 - Linux software RAID - /boot
- sdb3 - Linux software RAID - /

kenn
Posts: 17
Joined: 2014/07/06 09:25:44

Re: /boot/efi partitions on software RAID1

Post by kenn » 2014/07/07 11:18:14

Thank you for your quick response again!
I am not well versed in Linux so much,
So please teach me some points.
- sda1 - FAT32 - /boot/efi - in firmware boot menu as "CentOS"
I think it's OK.

But,I cannot understand the next.
- sdb1 - FAT32 - copy of /boot/efi - in firmware boot menu as "CentOS Backup"
How can I "copy" the /boot/efi?
How can I "menu" the "CentOS Backup"?

It may be a dull questions,
please forgive my ignorance.
Thank you.

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Super Jamie
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Joined: 2014/01/10 23:44:51

Re: /boot/efi partitions on software RAID1

Post by Super Jamie » 2014/07/07 11:35:24

For the first, you can use dd or cp commands.

For the second, use efibootmgr command.

kenn
Posts: 17
Joined: 2014/07/06 09:25:44

Re: /boot/efi partitions on software RAID1

Post by kenn » 2014/07/07 11:39:08

Thank you for your kindness.
I will try it later.

kenn
Posts: 17
Joined: 2014/07/06 09:25:44

Re: /boot/efi partitions on software RAID1

Post by kenn » 2014/07/08 10:03:10

Hello.
I tried Jamie's advice just now.
(Please forgive me for the time lag.)
But I cannot have a conviction about what I have done.
Would you confirm my procedure?

Code: Select all

# dd if=/dev/sda1 of=/dev/sdb1
# efibootmgr --create --disk /dev/sdb --label "CentOS Backup" --load "\\EFI\\redhat\\grub.efi"         
After this, on UEFI BIOS boot menu, "CentOS Backup" menu is appeared, and I can boot from this menu.

Is this the correct procedure?
And is this all to do for me?

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Super Jamie
Posts: 310
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Re: /boot/efi partitions on software RAID1

Post by Super Jamie » 2014/07/08 11:20:59

That's it as far as I know.

kenn
Posts: 17
Joined: 2014/07/06 09:25:44

Re: /boot/efi partitions on software RAID1

Post by kenn » 2014/07/08 13:18:04

Thank you!

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