On 10/26/2014 09:24 AM, Timothy Murphy wrote: > Ted Miller 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? > >> 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. > > Thanks very much for your response. > A couple of comments: > > 3. Curiously, I see I already have a file /boot/grub2/grub.cfg > on my CentOS-6.5 system, > though /etc/grub.conf points to /boot/grub/grub.conf . > Did I create the grub2 file while experimenting with the system, > or is it provided by CentOS-6.5 to simplify upgrading? Never had that happen, so can't comment. > > 3b. When I upgraded another server to CentOS-7 > it did not seem to find the old CentOS-6.5, > although it found a Windows system OK. > > However, I was using the old /boot partition for the new system. Sounds like it was looking for /boot/grub, and you over-wrote that when you installed the new system in the old /boot partition. I have gotten in the habit of either creating or leaving unused some space on any disk that might be used as a boot disk, rather than committing all the space to LVM. That way I have something to work with if I need "yet another" boot partition. > I'll try mounting the old boot as /mnt/C6 in the custom setup > during the new installation, as you suggest. > I shall not give a separate partition for the new /boot - > hopefully I shall be able to move /boot to a new partition later. > > I had thought, as an alternative method, of cloning the old system > to a new partition, and trying the new CentOSUpgradeTool on this. > (I'm running a CentOS-6 KDE system, and note that the documentation > for the new tool says it will probably not work with KDE or Gnome - > which I would have thought would rule out 95% of systems - > but it wouldn't matter too much if I still had the old system.) I have not tried an upgrade, but it sounds like they put the work into making server upgrades easier, but did not (or could not) make it as easy for desktop installations. Most people paying license fees are covering servers. Ted Miller Elkhart, IN, USA