RE: Live Upgrade for Linux

Kelly,

What I have done on some critical servers is create a /alt_root under which I do a dump piped to a restore into this directory. I then patch/upgrade my system leaving this directory alone. I then adjust the file /alt_root/etc/fstab to the correct device parameters. Then, if something goes wrong, then I can simply change my 'root' kernel parameter in grub or lilo and boot off of the original partition.

As a technical detail, I believe that you could even use the same /boot partition; this partition does not change radically in upgrades, and should be usable as long as the old kernels and initrd images were saved. I cannot verify this because I usually have not created /boot partitions. Silly me.

> Its a complete boot environment copy that you can do anything
touch
> the 'live' environment.

As far as the ability to do an upgrade to an alternate directory tree while leaving the existing running environment stable...I don't think it exists in the linux world. Please let me know if it does.

-Daniel Rohan

-----Original Message-----
From: Kelly Sauke [mailto:ksauke@fastenal.com] Sent: Tuesday, March 25, 2003 2:20 PM
To: Kelly Sauke
Cc: focus-linux@securityfocus.com
Subject: Re: Live Upgrade for Linux

Maybe I need a little clarification of what Live Upgrade does. I've gotten a lot of response of what I would call installer utilities but not a Live Upgrade (if I'm wrong please point it out to me). What Live Upgrade does under solaris is it creates a complete alternate boot environment with a root /usr /var and any other filesystem you want. Then you can apply patches etc to this other boot environment and boot off of that. If there is something in the patch that doesn't work or screws up the machine, then you just reboot off the original boot environment and you're back to where you were before upgrading and still

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have access to the patched boot environment to fix it. Its great for upgrading production type servers because the 'back out plan' if you will is nothing more than reboot off the old boot environment. In other

words you have 2 / filesystems, 2 /usr's, 2 /var's as well as 2 kernels. Its a complete boot environment copy that you can do anything to and then just reboot off the new environment without having to touch the 'live' environment.

For those that were asking, I'm running RedHat Advanced Server. I appreciate the responses.

Thanks,
Kelly

Kelly Sauke wrote:

> Does anyone know of any software for linux that acts similar to "Live
Received on Fri Mar 28 16:32:14 2003