Clustering is not trivial – latest forthcommings

As mentioned before, we are trying to cluster 2 (rendering) WISE Servers working onto one central ZODB. The tool in use to enable this on the ZOPE Level is Zope Enterprise Objects.

Just before I take of: If you try this and follow the How2, do yourself a favor and start of with:

  • a. a clean database to begin with
  • b. a sound WISE installation that works stable on your Database.

Why I highlight this? Guess.

As far as it goes, I can tell you, ZEO generally works, and everything the ZOPE Book (in the Development Installation Option) says about clustering is well true.

On the ZEO Server Side, timing is an Issue to give you a smooth ride on your data.
So for starters, it is not a good Idea to move out the data portion (aka Instance_home) of the WISE Server to a network attached storage device at the same time as you are trying to produce a stable clustering between two (or more) Rendering Machines and a database server.

Secondly: if you start out with a flaky ZODB i.e. with loads of broken links on the WISE Pages, or a ZODB that didn´t pack easyly on your old Installation. you can not tell, wether your DB or the way it is set up does pose any problems you are facing.

The above about tells you where we are after a weeks worth of work both on migrating content from two servers, and working out all the Link issues. (remember my Performance Issues on the TIDEPEDIA?)

Not that it is all that bad……. If it runs it is really hot. But unfortunately we didn´t get it to run stable, due to the above dont´s.

What now?

Since we are somehow committed to success, we are back at square one, starting out with a virgin ..\var\ filling it up with the data from the old Installation Site by Site and checking the Links at the same time with a free profiler called funnel web profiler by QUEST.

The Instance is now moved back to the ZEO Server local Raid storage (which helps a lot)

I keep you posted……..

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