[Zope] ZEO with Multiple Storages

[Martijn Pieters]

On 9/14/06, Jonathan <dev101 at magma.ca> wrote:
> If you mean having zope commit a single transaction to multiple storages,
> then 'vanilla' zope won't do it (Zope Corp has a commercial product called
> ZRS which does this type of thing).

No, that's not true. ZRS is used to create hot read-only or stand-by
copies of a ZEO server (and all storages within such a server are
copied).

One ZEO server can deal with multiple storages just fine. Transactions
involving multiple storages commit just fine.

> First off, does this make any sense? Is it worth pursuing?

I think so.

I would think, but do not know for sure, that transactions only
involving one storage should not delay transactions involving other
storages.

> Secondly, I
> assume that where an object is stored does not limit what other objects it
> can access in a transaction (e.g. object A could add a property to object
> B if they were in different storages) because all changes would occur in a
> client. (this ties into the single transaction committing to multiple
> storages)

You assume correctly.

Note that a stock Zope install already runs multiple storages; one for
Session data (tempstorage) and one for all other data.

> Lastly, any thoughts on how we could split up our existing data.fs file?
> One thought I had was to attempt to import/export data.

Either before or after upgrading to 2.9 (probably best after to take
advantage of the more robust ZODB), export and import.


-- 
Martijn Pieters