[CentOS] Anything Like Solaris' Live Upgrade?
warren at etr-usa.com
Wed Jan 30 00:36:14 UTC 2013
On 1/29/2013 12:03, Tim Evans wrote:
> I suppose it's not possible in
> this forum to ask such a question and not get into religion. Kinda like
> the U.S. Congress.
Um. Yes. <shakes head to clear the loony>
I know you think you're asking for an additional freedom that you feel
CentOS doesn't provide, but what you're really looking for is a reason
to go back and shackle yourself to a proprietary technology.
Wise man say: "Free your mind...and your ass will follow." Wise man was
on acid when he said that but the point...the POINT I say...is that
you're being trapped by a material desire which if satisfied costs more
than it's worth when you add in *all* the costs. Kinda like a jelly
doughnut. A really big, expensive jelly doughnut.
In addition to the problems with proprietary technology, there's at
least one more problem with Solaris' boot environment snapshots: they
take space, and space costs money. Oh, you say, it "only" costs a few
tens of gigabytes for each system version upgrade. What's the problem
in today's terabyte world?
Here's the problem: You want to set up a Solaris VM for development and
testing, and read that Solaris needs just 7 GB or so to install
everything, so you generously give it 20 GB on your laptop. Life is
fine: you install some additional software, you do your dev work, you
iterate. Then six months later an OS upgrade comes out, you attempt to
install it, it runs you out of disk space creating the snapshot, and
then fails to boot. (Yes, actual genuine war story. Made in USA.)
But wait, weren't snapshots supposed to save me from unbootable systems?
Sure, as long as you have prodigious free disk space. I don't know
about you, but several gigs of free disk on a VM still feels like a lot
You get bit other ways by this feature, too. It requires ZFS, which by
most accounts requires 64-bit CPUs and a gig of RAM per terabyte of disk
just to manage it. This means that if I give up on my reasonable wish
for a 20 GB VM and give it a dedicated HDD or three to play with, now I
have to go and set aside beaucoup RAM for it, too. Or maybe a whole system.
I'm not saying that all of this is out of reach. Yes, I get the fact
that I'm bitching about under $1000 of hardware. My point is that
features have a cost, and different OSes "charge" you different amounts
through their designer's choices about which features to include and
which to skip for now.
In the end, we are in fact talking rationality here, not religion. How
much do you want to pay for those features? TANSTAAFL.
> FWIW, Solaris' problems are not technical. Rather, they're Oracle's
> licensing and support policies that have essentially fired all its small
> system customers.
That pool is deeper than you realize.
Maybe above you were rolling your eyes at my wish for a usable 20 GB
Consider this: I have five or six flavors of Linux on that laptop, plus
all the BSDs, Windows 8, and the native OS X. When it comes time for me
to test a new version of my software, guess which OS it isn't going to
get tested on, purely because I can't afford to dedicate a whole system
to it? Or if I *am* fortunate enough to be able to afford a dedicated
OpenSolaris box, it's a good chance it isn't where I am now, so it might
as well not exist.
Do you expect developers like me to multiply the cost by 2, 3, 4x just
so we can have a dedicated test box at every development location? Or
maybe punch holes in firewalls so we can remotely use a remote box on
the back-end somewhere; that isn't "free" either, once you tally the
security risks it buys.
Here's why you care about my development problems: if my software
doesn't work on your platform, what does it cost you to do the fixes to
it to make it work, or seek out an alternative that does work?
How many more are there like me who also might like to test on Solaris
occasionally if it were easy, but don't because it isn't? How many
packages are there with Solaris portability problems as a result? I'd
guess there are hundreds of such packages that you personally would like
to use, but either can't, or could if you wanted to put in the time to
port them yourself.
All this because Solaris chased the high end at the expense of the
What's happening today to Solaris is simply what happened to all the
lesser proprietary Unixes before it. The market's been dissolving from
the bottom, and now the mountaintop is dissolving, too.
It's the old UnixWare vs Linux arguments, recapitulated. You remember
how that story ended, don't you?
Yes, I know you're switching to Linux now. What I'm trying to get
across is that you should take Linux on its own terms, not try to force
it into the Solaris mold. It is the way it is for a pile of good,
 Generous = 10-50% of the free space on a typical laptop SSD.
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