[Zope] Zeo question

[Jonathan]

----- Original Message ----- 
From: "Maciej Wisniowski" <maciej.wisniowski at coig.katowice.pl>
To: "ian" <ian at inpa.gov.br>
Cc: <zope at zope.org>
Sent: Tuesday, December 12, 2006 4:00 PM
Subject: Re: [Zope] Zeo question


>> 2. I can create a custom skin on each zope (in reality plone) instance
>> right or is each zope instance is just a mirror of the other?
> Nope. It is something different. In general ZEO is about sharing ZODB
> (Zope Object Database) between few Zope instances. There is no mirroring
> but just one ZODB. ZODB is a place where all objects you have created
> through ZMI (Zope Management Interface) are hold.

Scripts and external methods can also create objects which are stored in the 
ZODB


> When you have standard setup (one Zope instance)
> it has it's own ZODB (you may see this in <instance>/var/data.fs.
>
> With ZEO you have ZEOServer that holds ZODB (data.fs file) and multiple
> ZEO Clients that are connecting to it. ZEOClient is a normal
> ZopeInstance that is not using it's own data.fs (ZODB) but shared one.

Each zope instance can access multiple ZODB's (as Maciej mentions later), 
which means that the zope instance can access both a shared zodb and a local 
zodb which is specific to the zope instance.


> Because of this, every object created/changed/removed on one ZEOClient
> is removed from shared ZODB therefore all ZEOClient see this.
>
> There is more things that can be done. You may for example define (in
> zope.conf) mount points for folders that are individual for each zope etc.
>
> -- 
> Maciej Wisniowski

You could store all objects in a shared zodb, even objects which are 
specific to a single zope instance (and control access via permissions, 
application logic, etc). And you can create objects in a local zodb  (which 
would only be accessible by the local zope instance).

Zope is very flexible!  You just need to build a configuration which meets 
your use case!

hth

Jonathan