[RETRANSMIT] Re: [Mailman-Developers] Debate about Mailman on BytesForAll

[Kevin McCann]

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