[ZODB-Dev] Replicated ZEO

[Toby Dickenson]

On Wed, 10 Apr 2002 12:13:27 +0200, Godefroid Chapelle
<gotcha@swing.be> wrote:

>>Such that no transaction completes before the data is safely written
>>to hard storage on more than one node?
>
>This is too much in my customer's case.

Then you have many options. lucky you ;-)

>>Such that no node is more than x minutes out of date? ZSyncer would
>>work. I prefer the low-tech approach and just rsync the underlying
>>files.
>
>I do know the concepts underlying rsync but do not know if it can work =
on=20
>data.fs while zope is accessing it.

While zope is reading, definitely yes.

While writing.... I dont know whether rsync guarantees this to work,
but Ive never seen it go wrong. If you are paranoid, and your data.fs
is small, the cheeky solution is to take a local copy of it and rsync
the copy.

Someone else on this list has a script that syncs the appended tail of
data.fs. This (and the rsync case) are generally safe because
=46ileStorage generally only appends to the file. You should be able to
find this in the list archive.



Toby Dickenson
tdickenson@geminidataloggers.com