[Seaside] Re: in-image data saving

Michal michal-list at auf.net
Fri Sep 9 08:05:09 CEST 2005


Avi - 

> just using OSProcess to fork and save timestamped copies of the
> image every N minutes is looking pretty good right now.  The
> question is whether you can find an acceptable value of N: high
> enough that you're not using all of your resources on image saves,
> low enough that you're unlikely to ever lose more than a single
> transaction

One strategy I have found pleasant is a combination of regular
snapshoting and saving changes to disk between snapshots (which
basically amounts to journaling). That solves both the issue of
"keeping pace with a changing data model" (you're never reading in old
data) and the issue of losing more than a single transaction
(transactions since the last snapshot are on disk), while retaining
much of the simplicity of in-image data.

Michal


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