[Mailman-Users] Mailman + giant lists + the infinite weight of the cosmos

Brad Knowles brad at stop.mail-abuse.org
Fri Feb 11 16:00:35 CET 2005

At 1:50 PM -0800 2005-02-08, Cabel Sasser wrote:

>  One question I just posed to Carl via e-mail is in regards to Python 2.3
>  using this new "db package" for the pickles. I'll repost it here for the
>  sake of the archives.

	One thing I just remembered -- if you use Berkeley DB as a 
storage format for either individual pickles, or the entire list, 
then you break the ability to use NFS as the filesystem type.  The 
problem is that Berkeley DB makes heavy use of mmap() calls to access 
the data, and mmap() doesn't work on NFS.

	I don't know if the same problem exists with other *dbm style 
database file formats.

	The Mailman developers have worked pretty hard to write their 
code in such a way as to avoid all the known serious issues with NFS, 
and there are a number of people on the list who are using this 
functionality.  If the addition of Berkeley DB was to be added to the 
code base as an option for list/pickle storage, it would have to 
default to "off", and there would need to be appropriate warnings 
placed around the code and in the documentation regarding the 
incompatibility with NFS.

	But it's a great idea!

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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