Was working with an old CentOS 5.2 software raid and trying to replace the 70GB drives with 500GB drives. Had quite a bit of difficulty with grub not working when trying to boot on one drive or the other after repartitioning the drives.<\/p>\n
This comment<\/a> seems to have come to the rescue: After that, I tested booting from one drive and then the other, both were able to boot on their own – OK! On to growing the raid, after some fun with Knoppix Qparted to get the drives partitioned to use as much space as possible and keep swap at the end.<\/p>\n Somewhere along the way I had to set the partition type with the instructions found on this page<\/a> Once I was (finally) able to boot from the repartitioned drives, ran this to increase the raid size: then after things finished syncing up, ran this to actually get that space available: Repeated steps 4 – 11 before rebooting to test that the raid can boot off either drive.<\/p>\n","protected":false},"excerpt":{"rendered":" Was working with an old CentOS 5.2 software raid and trying to replace the 70GB drives with 500GB drives. Had quite a bit of difficulty with grub not working when trying to boot on one drive or the other after … Continue reading
\n1) Connect both drives and verify that all drives are sync’d (i.e. “cat
\n\/proc\/mdstat”)
\n2) If not, add the missing drive (i.e. If \/dev\/sdb1 is missing, “mdadm \/dev\/md0
\n–add \/dev\/sdb1”)
\n3) Wait for drives to sync up.
\n4) grub
\n5) grub> device (hd0) \/dev\/sda
\n6) grub> root (hd0,0)
\n7) grub> setup (hd0)
\n8 ) grub> device (hd0) \/dev\/sdb
\n9) grub> root (hd0,0)
\n10) grub> setup (hd0)
\n11) grub> quit
\nfdisk \/dev\/sdb
\n> t
\n> 1
\n> L
\n> fd
\n(sets partition 1’s type to Linux raid autodetect.)
\nRepeat for partition 2 (ie replace ‘1’ above with ‘2’)<\/p>\n
\nmdadm -G \/dev\/md0 –size max
\nwatch -d cat \/proc\/mdstat<\/p>\n
\nresize2fs \/dev\/md0<\/p>\n