Ken Jones wrote:
>
> Dave Weiner wrote:
> >
> > I've installed vpopmail/sqwebmail/courier-imap/qmailadmin on a small system
> > (< 200 users spread over ~40 domains) and it works like a champ and I love
> > it.
> >
> > I'm working on a project for a large client, and I've got them willing to
> > look at a qmail/vpopmail/sqwebmail/courier-imap/qmailadmin solution instead
> > of outsourcing their e-mail, so I've got a couple of questions.
> >
> > They currently have ~1,000,000 (yes, 1 million) mail boxes and growing
> > spread over ~30 domains. The biggest single domain has ~400,000
> > users/mailboxes. As new users get added, I have a feeling that the
> > rebuilding the cdb file for authentication is just not going to be
> > practical. Is MySQL with the --enable-large-site=y the best choice?
> >
> > Is anybody running qmail/vpopmail with ~400,000+ users/mailboxes? If you
> > are, would you e-mail me privately with your platform (OS and hardware), and
> > any loadbalancing you may be doing?
> >
> > TIA,
> >
> > Dave Weiner
>
> I would definitly go for mysql over cdb format.
>
> What the large site option does is create a table per domain instead
> of one table with all domains in it. This has two trade offs
>
> 1. with large site = yes you will save the space for the domain name.
> For example: with a domain name = 20 characters and 400,000 users
> you will save 8Mega Bytes of storage space. Which is significant.
>
> 2. The draw back of large site = yes is that mysql uses a file
> descriptor
> per table. I think mysql normal keeps up to a maxium of 20 open
> tables.
> So if you have 20+ active domains, mysql will be opening and closing
> database table files, which will slow down performance.
This is tuneable with table_cache.
See section 12.2.4 How MySQL Opens and Closes Tables in the MySQL
manual. This can be set to a large number - but you may run into OS
limits.
Hope that helps
Greg
>
> Ken Jones
