[CentOS] Anything Like Solaris' Live Upgrade?

Mon Jan 28 18:14:51 UTC 2013
Tim Evans <tkevans at tkevans.com>

On 01/28/2013 01:05 PM, xrx wrote:
> On 01/28/13 21:27, James A. Peltier wrote:
>> ----- Original Message -----
>> | Does anyone know of any sort of Linux utility that does something
>> | like
>> | what Solaris' Live Upgrade
>> | (http://docs.oracle.com/cd/E19455-01/806-7933/index.html) does?
>> |
>> | In my past life as a Solaris sys-admin, I found this an extremely
>> | useful
>> | tool for upgrading and patching running systems, as well as for
>> | maintaining redundant boot environments on separate system disks for
>> | disaster situations.
>> Nothing really until BTRFS comes of age.  I suppose you could snapshot your LVM volumes before performing the upgrade but to my knowledge there is nothing similar to Live Upgrade for CentOS
> It does sound like you can do the roughly the same with LVM snapshots.
> Reading the introduction of the solaris document you linked; it seems as
> if the solaris upgrade is applied on say a snapshot; and then the system
> is rebooted into the upgraded environment; and if it works, great, if
> not you need a reboot back into the original state.
> Wheras with CentOS 6; you take a snapshot of the root partition (easy as
> "lvcreate --snapshot --name RootSnapshot --size 2G /dev/VolGroup/Root"),
> and then do an upgrade with a reboot. If it works; you're set, if not,
> just revert back to the snapshot (lvconvert --merge
> VolGroup/RootSnapshot) and reboot; you'd be back to the state before the
> upgrade.

Thanks. You also need to manage the grub and fstab configurations to 
allow the second boot environment to be visible, bootable, and mountable.

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