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

Carl Zwanzig cpz at tuunq.com
Fri Feb 11 18:50:37 CET 2005

In a flurry of recycled electrons, Brad Knowles wrote:

> 	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.

Assume it does (I haven't actually checked). Just about all database-like
things tell you not to use them on any kind of NAS. This goes for low
level packages like *db* and commercial DBs like oracle & clearcase.

BTW, it's not just a mmap problem. The bigger problem is guarenteing
all writes happen in the way that the program expects, you want as
close to atomic transactions as you can get.  

(Some vendors have qualified various NAS boxes for supported configs,
usually this means NetApp. Don't try these packages on generic nfs.)


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