[OpenIndiana-discuss] Zones document (Was: Buildable distro?)

[Jim Klimov]

On 2013-02-06 17:49, Gary Mills wrote:
> On Wed, Feb 06, 2013 at 04:00:44PM +0000, Stefan Müller-Wilken wrote:
>>
>> I'm strongly with you in that putting proper zone setup into a
>> how-to as an optional but possible step is cool. Even more as it
>> gives you the security of being able to reduce the risk that
>> installation of dependency packages always imposes. And it shows off
>> on one of OIs core features. =-)
>
> In particular, I'd like to see what changes in planning or design are
> required to accomodate zones.  Is it more memory?  Is it more
> disk space?  What about additional filesystems?
>


You don't know? ;) Or is it an RFE to enhance How to build illumos? ;)

Regarding memory, on most systems the build zone's overhead is
negligible - its operating environment would eat some 50Mb or so
to run its copy of the daemons.

More filesystems - likely yes, and speaking of clones, rollbacks
and so on, it is not exactly a "minus".

Disk space - maybe, about 250Mb to install a default zone in OI.
When you have one, you can clone it as a template, so further
overheads shrink. And if your box is good for dedup, and if you
keep zone roots in rpool, then the zone roots might require no
extra storage for the software images - but at the dedup costs.
Given that the zone roots may be compressed and the default OI
installation rootfs can't (though I do like jumping through
these particular hoops), the storage space overheads with a
build zone's software might actually be less than doing it in
the GZ's rpool.

Whatever you use compared to a default OI installation - the
compiler and dependencies, the source code replica, the scratch
areas to hold the build and resulting packages (some 3-6Gbs)
you would sacrifice in any case, whether you build in your
rpool/export/home/jack in the GZ, or in a dedicated zone.

Overall, I'd say the added overhead is a bit more complex
setup and more routine, however it allows you to quickly
provision (clone) a whole new zone to work on a new bug with
a cloned source repository, without interfering with your
other yet-un-integrated works, and with near-zero resource
costs. And for newbies to OpenSolaris descendants, this is
a good lab experience to understand the zones and ZFS ;)

//Jim Klimov