OK, one other tidbit: The EFI BIOS has a UUID in its boot options. I expect that this identifies the old system disk, but I don't know where that UUID comes from. It is NOT the VFAT UUID for the EFI partition and is not any of the UUIDs for any of the Linux file systems or RAID arrays, or really anything else I can find under Linux. I'm guessing it is something the EFI BIOS has come up with, but I am not sure what exactly. *I* don't remember filling that in -- I think anaconda filled it in during the install process, so presumably, there is some magic under Linux to get this UUID (for the new disk(s)) and fill it in, but I cannot figure out what. Maybe efibootmgr has something to do with it, but efibootmgr does not work, either on a live system or a system booted from a DVD (CentOS 6.9 boot/install DVD) -- efibootmgr wants a kernel module named efivars that does not seem to exist. At Mon, 28 May 2018 18:25:39 -0400 (EDT) CentOS mailing list <centos at centos.org> wrote: > > OK, I wanted to replace the 500G disks in a Dell T20 server with new 2TB > disks. The machine has 4 SATA ports, one used for the optical disk and three > for the hard drives. It is set up with /dev/sda and /dev/sdb with each three > partitions: > > 1 -- VFAT (for EFI) > 2 -- ext4 (for /boot) > 3 -- LVM > > /dev/sda2 and /dev/sdb2 are a mirror raid (/dev/md0) > /dev/sda3 and /dev/sdb3 are a mirror raid (/dev/md1), with LVM on top of that. > > /dev/sdc is a disk containing one file system and mostly used by AMANDA for > backup (it has a "virtual" tape changer). > > This morning I shut the machine down and pulled [the 500G] /dev/sdb and > installed a new 2TB disk as a new /dev/sdb. Partitioned it (with parted) to be > much like /dev/sda (except partition 3 is way bigger). I added the new > /dev/sdb2 to /dev/sda2 (boot raid set) and dd'ed /dev/sda1 to /dev/sdb1. I > then created a new RAID set (degraded) with /dev/sdb3, used pvcreate on it, > used vgextend to add it to the system volume group, then used pvmove to move > the extents from the old disk to the new disk. Meanwhile I partitioned a > second 2TB disk using a USB SATA dock and copied the old 500G /dev/sdc1 to the > new 2TB disk. So far so good. > > Then I shut the machine down, swapped in the new backup [2TB] disk and pulled > the old system [500G] disk and installed the third new [2TB] disk. The system > won't boot that way. It seems there is something in the UEFI (secure boot) > logic that wants the original disk, even if everything is moved over. > > I ended up putting the original /dev/sda in. The machine boots and is using > the new system disk (a raid array in degraded mode). > > What is the magic to fix this? > > I tried to run efibootmgr, but it wants a model named efivars loaded, but > there is no such module available. > > What am I missing? > -- Robert Heller -- 978-544-6933 Deepwoods Software -- Custom Software Services http://www.deepsoft.com/ -- Linux Administration Services heller at deepsoft.com -- Webhosting Services