[ZODB-Dev] Use of fsync in FileStorage

[Tim Peters]

[Toby Dickenson]
>> ...
>> Replication alone wont help you here.... the damage caused by this
>> defect might be undectable until its too late.

[Neil Schemenauer]
> Huh?  As I understand it, ZODB does replication at the transaction level.
> It's not simply synchronizing the underlying file.  Why doesn't that
> help?

I don't know what Toby had in mind by "replication", but I believe you had
ZRS in mind.  ZRS works by network-broadcasting storage-API calls, not by
comparing or copying file bytes, so ZRS indeed shouldn't care.  It looks
like DirectoryStorage's idea of replication is based on file
synchronization:

    http://dirstorage.sourceforge.net/replica.html

> ...
> FWIW, I've added an fsync() call to the Durus FileStorage implementation.
> It shouldn't hurt performance and might make people feel better.

So you *are* superstitious after all <wink>.  An fsync() call will
definitely help on Windows (although I don't know whether Durus runs on
Windows).