On 10/25/2014 09:40 AM, Timothy Murphy wrote:
I would like to upgrade a CentOS-6.5 home server to CentOS-7 on a new partition. What is the simplest way to achieve this? I would like to be able to boot into either version of CentOS until I am sure the new version is running OK.
Incidentally, I think most people today must have enough space on their hard drive to install a new OS on a new partition - it is surprising that this option never seems to be mentioned in upgrade documentation.
A couple of observations after doing this:
1. It requires a custom disk layout, but is not particularly hard. 2. AFAIK, you can share your SWAP partition between the two installations. 3. Centos 7 uses grub2 as its boot loader. It is significantly different from "legacy grub" used in Centos 6 and before. a. It uses a configuration file that is auto-generated, and not supposed to be edited. b. It is capable of finding other installations (including legacy grub and windows), and creating links to them. c. 'b' only seems to work IF the other boot partitions are mounted somewhere in your file tree. What I have done is mount the other partitions (the /boot partition, if it is on a separate partition, otherwise /) under /mnt (e.g. /mnt/C6) when you are doing your custom disk layout. As long as they are mounted somewhere in the file system, grub2 seems to find them OK, and add them to your boot menu. It is apparently incapable of looking on unmounted partitions and finding Operating Systems lurking there. d. grub2 is (theoretically) capable of booting off of LVM (and I have done so successfully), BUT that capability is disabled and unsupported in RHEL/Centos 7. You still have to put /boot on a non-LVM partition.
Ted Miller Elkhart, IN, USA