[Zope] Multiple ZODB for virtual hosts with ZEO

[David Pratt]

Hi Dieter!  This is really nice to know.  Zope is really flexible and 
so awesome as a result.  If I wanted to configure with multiple zodb 
for a single ZEO server you say there may be a possible downside in 
requiring a single ZEO server per database instance further down the 
road.  Is this something that is currently planned so I don't implement 
something that will  not be supported later?  It could be also be a bit 
of a problem since each ZEO server requires its own RAM.  RAM is a 
valuable commodity.

My goal is to ensure that customers I work with are working exclusively 
in their own zodb.  It seems preferable for these zodb's to be 
associated with a single ZEO server (instead of each zodb mounted in a 
single zope instance) to make maintenance tasks smooth and handled 
asynchronously.  Would you agree? I realize that if resources were 
unlimited, it would be best for a single ZEO server to use a single 
zodb and have one or more ZEO clients.  My circumstance is that the 
virtual sites are relatively small, they make heavy use of the 
filesystem blobs and relational database storages to deliberately 
minimize the size and demand on zodb.  I can't see the zodb per virtual 
site growing to any more than 50MB in size for example.

I guess I see the possibility of single ZEO  for a number of virtual 
hosted sites as a plus (since it means also that I could add additional 
ZEO clients to provide more threads for serving the group of virtual 
sites). I guess I am just trying to determine the sanity of doing it.  
I see also with this possible arrangement I could move a zodb out into 
its own ZEO server and ZEO client situation if it was needed.  Many 
thanks.

Regards,
David

On Tuesday, September 20, 2005, at 02:23 PM, Dieter Maurer wrote:

> You can do this -- without ZEO, with a single ZEO (and multiple 
> storages)
> and with many ZEOs.