Convert default LVM-based CentOS 7 system to UEFI mode

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Quartz
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Joined: 2022/01/18 14:12:13

Convert default LVM-based CentOS 7 system to UEFI mode

Post by Quartz » 2022/01/18 14:52:10

I have a system installed in 256 GB SSD with the default disk partitioning using MBR. I need to convert to UEFI boot as it is preferred to disable CSM in BIOS to use Intel Rapid Storage capabilities.
df -hPT
Filesystem Type Size Used Avail Use% Mounted on
devtmpfs devtmpfs 94G 0 94G 0% /dev
tmpfs tmpfs 94G 404K 94G 1% /dev/shm
tmpfs tmpfs 94G 20M 94G 1% /run
tmpfs tmpfs 94G 0 94G 0% /sys/fs/cgroup
/dev/mapper/centos-root xfs 50G 36G 15G 72% /
/dev/sda1 xfs 1014M 525M 490M 52% /boot
/dev/mapper/centos-home xfs 184G 48G 136G 27% /home
tmpfs tmpfs 19G 32K 19G 1% /run/user/1000
(parted) print
Model: ATA INTEL SSDSCKKW25 (scsi)
Disk /dev/sda: 256GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number Start End Size File system Name Flags
3 17.4kB 1049kB 1031kB EFI System boot
1 1049kB 1075MB 1074MB xfs Linux filesystem
2 1075MB 256GB 255GB Linux LVM lvm
I was able to convert to convert the disk to GPT easily. However, I cannot accomplish the further steps needed to create the EFI System Partition. Most guides I found suggest shrinking the existing XFS partitions to leave a free space for /boot/efi, however, it is not straightforward to do it as it needs to be done in resque mode, and I'm not sure if it would be enough. Maybe there is some easier way I'm missing?

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TrevorH
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Re: Convert default LVM-based CentOS 7 system to UEFI mode

Post by TrevorH » 2022/01/18 15:13:07

Intel RST is their FakeRAID, right? Why would anyone want to use that on Linux. The recommendation is to disable it and use Linux software RAID.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

Quartz
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Joined: 2022/01/18 14:12:13

Re: Convert default LVM-based CentOS 7 system to UEFI mode

Post by Quartz » 2022/01/18 15:28:50

TrevorH wrote:
2022/01/18 15:13:07
Intel RST is their FakeRAID, right? Why would anyone weant to use that on Linux. The recommendation is to disable it and use Linux software RAID.
Well, it's questionable. To be precise, there is Intel VROC on my system. The position it as hybrid RAID:
Is Intel VROC software or hardware RAID?
Intel VROC is a hybrid RAID solution. It has attributes like hardware RAID because of the key silicon feature called Intel Volume Management Device (Intel VMD) which is offered with the new Intel Xeon Scalable processors. Intel Virtual RAID on CPU (VROC) utilizes Intel VMD to aggregate NVMe SSDs allowing bootable RAID. Intel VROC also has attributes like software RAID. For instance: it uses some of the CPU cores to calculate the RAID logic. Because of this combination of software and silicon, Intel VROC is called a hybrid RAID solution.

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jlehtone
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Re: Convert default LVM-based CentOS 7 system to UEFI mode

Post by jlehtone » 2022/01/18 15:30:44

Call it "hybrid" or "fake", it is neither genuine hardware RAID nor plain software RAID.
Quartz wrote:
2022/01/18 14:52:10
Most guides I found suggest shrinking the existing XFS partitions to leave a free space for /boot/efi, however, it is not straightforward to do it as it needs to be done in resque mode, and I'm not sure if it would be enough.
There is no "shrink" for XFS. Well, you can do it by (1) removing the filesystem/partition, (2) creating new, smaller volume with filesystem, and (3) restoring data to the new filesystem from backup.

If you can restore data from backup, then you can as well wipe the disk and reinstall CentOS 7 from scratch. Finally, restore data from backup.

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