[Zope-dev] Read only ZEO

[Tim Hoffman]

HI Dieter

I had a look at z2.py (it's actually -r) so any way I tried (not too 
successfully).

I have zeo running with 2.4.1 I have a zss and 2 zeo clients.
One running without -r switch and one running with -r

In z2.py the -r switch is documented as follows

  -r
   
    Run ZServer is read-only mode. ZServer won't write anything to disk.
    No log files, no pid files, nothing. This means that you can't do a
    lot of stuff like use PCGI, and zdaemon. ZServer will log hits to
    STDOUT and zLOG will log to STDERR.

Well when running a zeo client with -r switch results in no log files 
being written
and the log is written to STDOUT, but the ZEO client is definately not 
in readonly mode
ie I can create and modify documents.  (It probably means it can;t cache 
to disk ;-)

I need to track down where READ_ONLY flag is used.  There isn't an 
occurrance
with the ZEO code, so unless the READ_ONLY capability is implemented 
higher up
in the transaction service, thenI think it isn't going to work.

This document http://www.amk.ca/zodb/zodb-zeo.html which is linked to on 
the Zeo Product page
actually mentions using Zeo client in readonly mode. I wonder if anyone 
has actually done it?

Tim


Dieter Maurer wrote:

>Tim Hoffman writes:
> > In some of the overview documents discussing ZEO, there is reference
> > to a ZEO client potentially mounted a ZSS in read only mode. (I want
> > to have some ZEO's in read/write as well)
>When you start Zope with the "-R" option (I think, look at
>"z2.py"!), it is in read-only mode.
>
> > I have been trying to work out how this might be achieved
> > but have pretty much drawn a blank, has anyone done this I
> > have any idea how I might go about doing such a thing.
>There is a patch at
>
>  <http://www.dieter.handshake.de/pyprojects/zope>
>
>which allows Zope to be started with a read only storage.
>
>Maybe, you can adapt it for ZEO.
>
>
>Dieter
>