[Zope] Lost Objects after System Crash (Zope 2.1.5 on Win32)

[Martijn Pieters]

On Tue, Mar 21, 2000 at 09:59:40AM +0100, Joachim Werner wrote:
> > I upgraded to Zope 2.1.5 (Win 32) Saturday and carried out changes in the 
> > database (eg. created new ZClasses, added ZClass instances, etc.)
> > 
> > I had a nasty system crash (Win 95) around midnight Saturday. When I 
> > reopened Zope I realised the database was back to its 16:22 status:
> > - All new objects had vanished.
> > - The last transaction logged in the Undo list is dated about 16:22.
> > - The very Data.fs in the filesystem is stamped 16:22 if you can 
> > believe it.
> > 
> > I checked the Z2.log and it shows these missing changes. So I didn't dreamt 
> > doing them.
> > 
> > I suppose these changes are lost?
> 
> I had the same experience a few days ago with a 2.1.4 installation running
> under Win98. I have a couple of different Zope instances running on Linux and
> Windows, but that was the first data loss. It seemed to me as if the session
> had been running in "demo" mode so that changes would not be really persistent.
> As in Alexandre's case, I first thought I was dreaming because there was no
> hint of my data except for the log files.
> 
> I suggest some further investigation into that. If Zope really lost things that
> easily, I'd consider not using ZODB for production sites ...
> 
> BTW: In my case it also was a Windows system crash that caused the data 
> loss.

This sounds like Win98 is using a write-cache that didn't get flushed to disk
because of the crah. IIRC, Zope forces write cache flushes, but it could well
be that Win98, being a client-patform, ignores that for performance reasons.

Then again, who'd use Win98 for production sites?

-- 
Martijn Pieters
| Software Engineer    mailto:mj@digicool.com
| Digital Creations  http://www.digicool.com/
| Creators of Zope       http://www.zope.org/
|   The Open Source Web Application Server
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