software mirror of boot disk in Itanium rx2620 server

[manuel j hurtado m]

Hi ,
How can make a software mirror whith Red Had Enterprise 3 of a boot disk and his filesystems in a Itanium server rx2620.
Thanks.

[xyko_1 · Accepted solution]

Hi Manuel,

I don't know if RH E3 supports md (multiple devices) installation from the very beginning.

But if it doesn't you will have to follow some guidelines after the system installation.

Refer to
http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/Software-RAID-HOWTO.html

Hope it helps,
Xyko

[Ivan Ferreira]

The best way to do it is at installation time, you can create software raid partitions on the disks and then create a RAID.

It works fine because i did it once.

After installation, you can add and option to the EFI to boot from the mirror.

But if you want to do it AFTER the installation is tricky. You should check the howtos. (Software RAID HOWTO)

[manuel j hurtado m]

is in a initial installation , how i mirror the EFI partition for boot of both disk

[xyko_1]

Hi Manuel,

Here you have some good documentation that may guide you to what you want, if RH3 does not support initial installation of boot partition on raid devices.

http://howtos.linux.com/howtos/Software-RAID-HOWTO-7.shtml

Regards,
Xyko

[Ivan Ferreira]

During installation, mirror everything except the EFI partition (you cannot do it during installation because is vfat). But in the second disk, you need to leave a partition equal to the EFI partition on the first disk.

After the installation, you need to save the contents of the /boot/efi using a backup tool. Then you need to manually create the raid (using raidtab o mdadm), using the partitions (the actual boot/efi and the reserved on the second disk), create the vfat filesystem on it and then restore the backup. (See the howtos)

Then you can add the second disk as an option on the EFI shell.

Is not an easy task, but can be done.

[manuel j hurtado m]

can you explain me more detailed this part of copy the /boot/efi partition and mirroring in tha second disk please.
thnaks

[Ivan Ferreira]

The procedura is something like this (but not exactly):

tar cvf /root/efiboot.tar /boot/efi
umount /boot/efi

Edit /etc/raidtab

raiddev /dev/mdN
raid-level 1
nr-raid-disks 2
nr-spare-disks 0
chunk-size 32
persistent-superblock 1
device /dev/sda1
raid-disk 0
device /dev/sdb1
raid-disk 1

In /dev/mdN, N sould be the next available raid device. sda1 y sdb1 are the 150 MB partitions. sda1 is the current boot/efi and will be destroyed.

mkraid /dev/mdN

mkfs -t vfat /dev/mdN

mount -t vfat /dev/mdN /boot/efi

cd /

tar xvf /root/efiboot.tar

Edit /etc/fstab and replace /dev/sda1 on /boot/efi by /dev/mdN.