[Seaside] saving an image while serving

Philippe Marschall philippe.marschall at gmail.com
Mon Apr 18 12:00:36 UTC 2011

2011/4/18 Janko Mivšek <janko.mivsek at eranova.si>:
> Hi guys,
> Let me support Nevin claims strongly with my the same experiences with
> image based persistency. Anyone just enough pragmatic and with a bit of
> probability calculus can soon discover, how right Nevin is.
> I know that from my experience, ok, with VisualWorks images, which
> snapshot every hour. One such sole image hosts 50+ sites and in last 8
> years without any loss of data. We have just few crashes (around 2-4 per
> year) because of DOS attacks, and that's all.
> It is true that there is 1 hour window to loose data and that we had
> luck loosing nothing during those few (mostly nightly) crashes, but when
> I compare that with horror stories of friends using, say MySql...
> Of course such image is backup every hour, every night - just plain
> usual safety measures therefore.

Everyone how thinks image based persistence is a good idea please look
at SqueakSource. Not only do you suffer from the impacts of the
non-transactional behavior (yes, data got lost several times in the
past, the image hangs for quite some time when saving) you'll also
never be able to switch to a new version of your dialect and you are
limited to one image doing the processing.


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