[Setup] ZODB Replicated Storage experiences?

Christian Ledermann christian.ledermann at gmail.com
Thu Aug 15 10:02:10 UTC 2013

I would love to see a talk at ploneconf about
zrs vs relstorage vs neoppod vs [I am sure I missed something]


On Thu, Aug 15, 2013 at 12:45 PM, Gil Forcada Codinachs
<gforcada at gnome.org> wrote:
> Hi,
> No experience withe either (ZRS or relstorage) but really interested to dive
> into them relatively soon (~ before end of the year) so I'm really
> interested in this topic, please bring your experiences!
> Cheers,
> Gil
> 2013/8/15 Patrick Gerken <do3ccqrv at googlemail.com>
>> Hi,
>> a customer of ours has been using ZRS before it was open sourced. Two or
>> three weeks ago we found an issue that forced us to stop using zrs. We are
>> still waiting for feedback though. Maybe we are just doing something wrong.
>> Also, we are using an old version, so we do not have blob experience.
>> We did not notice any performance changes after we switched off
>> replication. So it seems to be without performance penalties. Both servers
>> are very close to each other though.
>> The way WE set up replication, there would be still a long delay between
>> failovers. I guess with the newer versions and zookeeper support you might
>> be able to keep you zeo clients running when switching from master to
>> secondary. I believe you still have to restart your secondary zeo server to
>> use a different configuration to act as a master. Else there is no writing
>> possible.
>> I am btw. interested in your Relstorage Setup. Are you using the released
>> version or the source checkout with the new features. What is the issue with
>> packing? Does it take long and degrades answer times?
>> Thanks an best regards,
>>         Patrick
>> On Thu, Aug 15, 2013 at 4:48 AM, Héctor Velarde <hector.velarde at gmail.com>
>> wrote:
>>> as many of you may know by now, ZODB Replicated Storage (ZRS) was
>>> released as open source software last May:
>>> https://bitbucket.org/zc/zc.zrs
>>> https://pypi.python.org/pypi/zc.zrs
>>> according to its documentation, ZRS "provides database replication for
>>> ZODB. For each database, a primary storage and one or more secondary
>>> storages may be defined. The secondary storages will automatically replicate
>>> data from the primary storage.
>>> "Replication is superior to back-ups because as long as secondaries are
>>> running, secondary data is kept updated. In the event of a failure of a
>>> primary storage, just reconfigure a secondary to be the primary, and it can
>>> begin handling application requests."
>>> in the past we have been using RelStorage for high availability and
>>> replication but we are not extremely happy with it because, at least on our
>>> experience, on sites with lot of content creation can DB maintenance
>>> (packing) can be a little bit problematic. besides that, you also have to
>>> maintain 2 different technologies.
>>> I just finished reading the documentation and, though fortunately it does
>>> not have doctest integrated, it also is not very clear, at least not for me.
>>> I think ZRS could be a killer feature for large, mission critical Plone
>>> sites.
>>> does anybody here has any experience with it? any configuration examples?
>>> how does a secondary storage behaves regarding blobs?
>>> best regards
>>> --
>>> Héctor Velarde
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>>> Setup mailing list
>>> Setup at lists.plone.org
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Best Regards,

Christian Ledermann

Nairobi - Kenya
Mobile : +254 702978914


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