Ted Miller wrote: >> I'm having trouble installing CentOS-7 on my HP MicroServer. >> I've tried with KDE LiveCD and Netinstall (both on USB sticks), >> and now I'm going to try with the DVD ISO. >> >> But I want to be quite sure I can return to CentOS-6.5 >> if things go wrong, so I'm wondering what precisely I need to copy >> (eg the MBR and a bit more) so that I could get back to things as they >> were. Is this documented anywhere? > You asked what to keep to be able to boot C6. From your narrative, it > seems that the legacy grub boot for C6 is already gone (blown away) by > your > C7 install. I haven't figured out enough about grub2 to be able to tell > you how to preserve your current grub2 configuration, but here are some > possible ways to keep C6 accessible: Thanks very much for your comprehensive reply. > 1. The Super Grub2 Disk from seems to be > pretty good at finding any and all possibilities for booting using new and > old versions of grub. I've downloaded this and will try it if necessary. > 2. If you are reinstalling into exactly the same location as your previous > C7 attempts (same devices for boot and root), just don't let the installer > update the boot information. Since you know it boots both versions now, > it should still boot both versions after the install. Yes, I'll try that - though I don't remember being asked if I wanted to update the bootloader - I probably missed it. > Not knowing what your installation problem is, I can't tell (and you may > not be able to tell either) if anything is wrong with your boot > information, or if that is OK. I'm pretty sure it gets through the code in the boot, since it says [OK] Reached target Initrd Default Target > 3. From C3, install legacy grub onto a USB stick, which would allow you to > boot directly to C6, without any requirement for anything to be on a hard > drive. I'm not sure what you mean by C3? I see that my CentOS-6.5 system has entries in grub/grub.conf which don't seem very old (January this year). I did wonder if one can in fact use grub with CentOS-7, since it seems to create an empty (almost) /boot/grub/ folder? > 4. It is also possible to set up a CD that will boot your computer, but I > don't remember the details of that. Not quite sure what you mean by this? > Hope one of these, or something someone else chimes in, will help you. > Also hope you get the C7 install figured out. So far I have only done it > from DVD, and those went well for me. I've found a second hard disk (from an old server) and put that in, so I'll be able to experiment with that, without worrying about what it does to my current CentOS-6.5 system. Also I used to use the old grub interactively - I'll see if it is still possible to do this with grub2. And I'll try a couple of your suggestions first, like not installing the boot-loader. -- Timothy Murphy e-mail: gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin 2, Ireland