bare-metal backup before update--options?

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Fred Smith

11 Feb 2019 11 Feb '19

3:04 p.m.

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:

1. 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. 3. 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!

Fred

-- ---- Fred Smith -- fredex@fcshome.stoneham.ma.us ----------------------------- "And he will be called Wonderful Counselor, Mighty God, Everlasting Father, Prince of Peace. Of the increase of his government there will be no end. He will reign on David's throne and over his kingdom, establishing and upholding it with justice and righteousness from that time on and forever." ------------------------------- Isaiah 9:7 (niv) ------------------------------

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Mike Burger

11 Feb 11 Feb

3:06 p.m.

Hi, Fred,

On 2019-02-11 10:04, Fred Smith 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. 3. 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!

I've been a big fan of Mondo Rescue. http://www.mondorescue.org/

-- Mike Burger http://www.bubbanfriends.org "It's always suicide-mission this, save-the-planet that. No one ever just stops by to say 'hi' anymore." --Colonel Jack O'Neill, SG1

Simon Matter

3:16 p.m.

...

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. 3. 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?

Regards, Simon

Fred Smith

12 Feb 12 Feb

12:01 a.m.

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. 3. 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?

Fred

-- ---- Fred Smith -- fredex@fcshome.stoneham.ma.us ----------------------------- The eyes of the Lord are everywhere, keeping watch on the wicked and the good. ----------------------------- Proverbs 15:3 (niv) -----------------------------

Simon Matter

9:39 a.m.

...

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

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Fred Smith
Mike Burger
Simon Matter