[RETRANSMIT] Re: [Mailman-Developers] Debate about Mailman on
BytesForAll
Kevin McCann
kmccann at bellanet.org
Thu Aug 26 22:57:55 CEST 2004
Brad Knowles wrote:
> At 4:10 PM -0400 2004-08-26, Dale Newfield wrote:
>
>> The biggest problem with BerkeleyDB is that it REQUIRES that the file
>> system support memory mapping the files. This means that you cannot
>> guarantee correctness if these files are located on an NFS mount.
>
>
> True enough. That's a known issue with BerkeleyDB.
>
> But why would you be putting any of this stuff on NFS anyway? And
> how would you deal with all the file locking issues? And
> cross-platform issues? I've been doing NFS for a very long time, and
> I have yet to see a mail-related environment where NFS is a good
> choice or works well. Given the sorts of things we're talking about
> doing, I can't imagine that NFS could possibly be a good solution.
>
I agree, Brad.
Barry has redirected some of the discussion over to
mailman3-dev at python.org. I'll crosspost for this message, but maybe we
should move over to mm3-dev? In any event, further to NFS, it seems
SQLite has issues, too. From the concurrency article I pointed to:
"SQLite uses POSIX advisory locks to implement locking on Unix. On
windows it uses the LockFile(), LockFileEx(), and UnlockFile() system
calls. SQLite assumes that these system calls all work as advertised. If
that is not the case, then database corruption can result. One should
note that POSIX advisory locking is known to be buggy or even
unimplemented on many NFS implementations (including recent versions of
Mac OS X) and that there are reports of locking problems for network
filesystems under windows. Your best defense is to not use SQLite for
files on a network filesystem."
- Kevin
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