In article CAAOM8FXumoSAgbDe+PzryraRUHcsWOjWJQf-3Mc0TSn4ODRt9w@mail.gmail.com, Matt matt.mailinglists@gmail.com wrote:
I installed Centos 6.x 64 bit with the minimal ISO and used two disks in RAID 1 array.
Filesystem Size Used Avail Use% Mounted on /dev/md2 97G 918M 91G 1% / tmpfs 16G 0 16G 0% /dev/shm /dev/md1 485M 54M 407M 12% /boot /dev/md3 3.4T 198M 3.2T 1% /vz
Personalities : [raid1] md1 : active raid1 sda1[0] sdb1[1] 511936 blocks super 1.0 [2/2] [UU] md3 : active raid1 sda4[0] sdb4[1] 3672901440 blocks super 1.1 [2/2] [UU] bitmap: 0/28 pages [0KB], 65536KB chunk md2 : active raid1 sdb3[1] sda3[0] 102334336 blocks super 1.1 [2/2] [UU] bitmap: 0/1 pages [0KB], 65536KB chunk md0 : active raid1 sdb2[1] sda2[0] 131006336 blocks super 1.1 [2/2] [UU]
My question is if sda one fails will it still boot on sdb? Did the install process write the boot sector on both disks or just sda? How do I check and if its not on sdb how do I copy it there?
Tests I did some years ago indicated that the install process does not write grub boot information onto sdb, only sda. This was on Fedora 3 or CentOS 4.
I don't know if it has changed since then, but I always put the following in the %post section of my kickstart files:
# install grub on the second disk too grub --batch <<EOF device (hd0) /dev/sdb root (hd0,0) setup (hd0) quit EOF
Cheers Tony