Software RAID And GRUB On CentOS 7
Hi,
When I perform a software RAID 1 or RAID 5 installation on a LAN server with several hard disks, I wonder if GRUB already gets installed on each individual MBR, or if I have to do that manually. On CentOS 5.x and 6.x, this had to be done like this:
# grub grub> device (hd0) /dev/sda grub> device (hd1) /dev/sdb grub> root (hd0,0)
grub> setup (hd0)
grub> root (hd1,0)
grub> setup (hd1)
grub> quit
I’d like my server to be able to boot a degraded software RAID after an eventual hard disk failure.
Any suggestions?
Niki Kovacs
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5 thoughts on - Software RAID And GRUB On CentOS 7
I have an aging FC14 (!!!!) system, w/ mdadm RAID partitions. I have
/boot setup as mdadm RAID1’s, 2 drives (actually partitions). Machine boots AOK, & I believe it does (& maintains) that setup automatically. I
got that recommendation from a mailing list ages ago, can’t remember where, sorry. $0.02, no more, no less ….
[root@Q6600:/etc, Thu Aug 11, 08:25 AM] 1018 # df -h Filesystem Type Size Used Avail Use% Mounted on
/dev/md1 ext4 917G 8.0G 863G 1% /
tmpfs tmpfs 4.0G 0 4.0G 0% /dev/shm
/dev/md0 ext4 186M 60M 117M 34% /boot
/dev/md3 ext4 1.8T 1.4T 333G 81% /home
[root@Q6600:/etc, Thu Aug 11, 08:26 AM] 1019 # uname -a Linux Q6600 2.6.35.14-106.fc14.x86_64 #1 SMP Wed Nov 23 13:07:52 UTC
2011 x86_64 x86_64 x86_64 GNU/Linux
[root@Q6600:/etc, Thu Aug 11, 08:26 AM] 1020 #
I too use this kind of set up. however I do not believe that anything on the MBR is updated automatically by any yum/rpm updates. Thus in this kind of a setup, one needs to take manual steps. HTH
Rob
Anaconda will install grub2 to each component device for BIOS boot on RAID levels 0, 1, 4, 5, 6, and 10. Under EFI, only RAID1 is supported.
https://github.com/rhinstaller/anaconda/blob/master/pyanaconda/bootloader.py
$ sudo grep grub2 /var/log/anaconda/program.log
This will get you the commands the installer used for installing the bootloader.
Chris Murphy