On Mon, Feb 11, 2019 at 04:16:38PM +0100, Simon Matter via CentOS wrote:
Hi all!
I'm a "nervous nellie", I have not yet updated my 7.5 desktop to 7.6 because (1) it has an Nvidia card, and (2) I've heard of problems upgrading on top of software RAID (using RAID1 with 2 drives).
I need to upgrade it to stay secure, and I want to do a bare-metal
backup
first (so I can put it all back as it now is, in case it explodes in
my
face), so I'm trying to figure out the safest way to do that. Here are the choices as I see them, I'd appreciate comments/thoughts:
- boot from live DVD and manually reassemble the RAID array (how
would I do that?) 2. degrade the array (with appropriate commands) so that it is running on just one drive, then boot a live DVD and use dd to back up that
drive.
- Other choices you can suggest?
then after successfully getting a bare-metal backup, reboot it with
the
full RAID array and run the update.
Thanks in advance!
To me the easiest method seems to:
- boot into rescue mode, not mounting any disks
- directly dd all complete disks to files on a USB disk or to a remote
host
- reboot and update as usual
If anything fails you can again boot into rescue mode (maybe with the help of USB/DVD/CD) and:
- recover all disks using dd from the backups made before
- reboot and be back on 7.5
Any reason why this shouldn't work?
Thanks for the reply!
by rescue mode, do you mean (1) the "rescue" kernel in the boot menu? Or (2) an option on one of the installer DVDs?
Wouldn't (1) boot from the existing drives and mount them?
I'm not sure about the rescue mode in CentOS 7 but booting from external media will work for sure.
Simon