To timidly go where many have gone before

I've been a Live Upgrade convert for about a year and a half. I have four boot environments on my workstation at home, two for Solaris Express and two for testing OpenSolaris builds. (Yes, two would be sufficient, and that's what I used to do until the second time I put an experimental build on top of my "stable" boot environment. It's impossible to make that same mistake if I have two stable boot environments.) But as great as Live Upgrade is, it has its shortcomings. For one, you have to reserve disk partitions for boot environments. You can't retrofit Live Upgrade onto an existing system. For another, initializing a boot environment takes time, as it's making a second copy of the OS. (And I'm sure other people have other complaints, but those are my main two.)

With the upcoming Indiana release, Live Upgrade has been replaced with Snap Upgrade. (As I understand it, Live Upgrade can't be open-sourced for some reason.) Snap Upgrade is ZFS-based, which has direct impact on my two main complaints. There's no longer a need to reserve paritions for additional boot environments, as boot environments are merely clones of the existing ZFS partitions. This saves on disk space, as the copy-on-write nature of ZFS means that multiple boot environments will likely point at the most of the same disk blocks. It also means that initializing a boot environment is effectively instantaneous:

# date && beadm create foo && date
Mon Apr 28 10:39:03 EDT 2008
Mon Apr 28 10:39:10 EDT 2008
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The new beadm(1M) command is used to manage boot environments. The command options are a bit simpler than the Live Upgrade commands and demonstrate their ancestry as being a mix of ZFS and Live Upgrade operations:

NAME
     beadm - utility for managing zfs boot environments

SYNOPSIS
     /usr/sbin/beadm

     beadm create [-a] [-e non-activeBeName | beName@snapshot]
         [-o property=value] ... [-p zpool] beName

     beadm create beName@snapshot

     beadm destroy [-f] beName | beName@snapshot

     beadm list [-a | -ds] [-H] [beName]

     beadm mount beName mountpoint

     beadm unmount beName

     beadm rename beName newBeName

     beadm activate beName

And some simple demonstration:

# beadm list

BE          Active Active on Mountpoint Space
Name               reboot               Used
----        ------ --------- ---------- -----
opensolaris yes    yes       legacy     2.74G
initial     no     no        -          60.5K
# for i in 1 2 3 4 5 ; do
> beadm create foo${i}
> done
# beadm list

BE          Active Active on Mountpoint Space
Name               reboot               Used
----        ------ --------- ---------- -----
foo1        no     no        -          81.5K
opensolaris yes    yes       legacy     2.74G
initial     no     no        -          60.5K
foo5        no     no        -          81.5K
foo2        no     no        -          81.5K
foo3        no     no        -          80.5K
foo4        no     no        -          81.5K
# for i in 1 2 3 4 5 ; do
> beadm destroy -f foo${i}
> done
# beadm list

BE          Active Active on Mountpoint Space
Name               reboot               Used
----        ------ --------- ---------- -----
opensolaris yes    yes       legacy     2.74G
initial     no     no        -          60.5K
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