I have tried Mnemonic a couple of months ago. It seems very promising, 
but I could not use it for web-based applications because it doesn't 
handle mulitple processes/threads/users very well.
It would be ideal if it is implemented with a strategy like Suneido 
(multiple version of a datastore, to provide a simple but reliable 
transaction mechanism):

http://www.advogato.org/article/250.html

Cheers,

   Erik.

Oliver Beddows wrote:
> Hello,
> 	I recently read an article on object prevalence at developerWorks.
> I have been experimenting with an implementation of object prevalence in 
> Ruby, called Mnemonic.
> 	I was wondering if anybody is using Mnemonic (or Prevalayer) as a storage 
> mechanism in any of their current projects? Also, can it be used within a 
> apache/mod_ruby environment for web-based applications?
> Regards, Oliver.
> 
> A link to the article:
> * http://www-106.ibm.com/developerworks/library/wa-objprev/index.html
> 
> 
> 
> 
>