[Kroupware] Web interface frontend

[Andreas Jellinghaus]

this concept with super scalability (via dns names,
everything in ldap, create config files via templates)
is not necessary for 99% of all configurations,
but adds to complexity.

the concept is comparable to the biggest mail systems
(like those used at multi-million domain web hosters),
and looking at the differences i don't see big advantages
in doing things different (for example one stage instead
of two stage or ldap instead of sql).

so in summary i don't see advantages in the highest end,
and for smaller systems i see probably unneeded complexity.


--cut--

i wonder who needs super scalability features.

starting with small companies: a single server does it all.

bigger companies gain something by using different systems
for outbound mail, incoming mail, virus scanning, mail
storage, ldap directory, webmail, webmail-session-database.

in this configuration the mail storage is the obvious bottleneck,
but load balances or round-robin dns can split the load to
several proxy imap servers, that will in turn find the real
imap server and thus allow splitting to several of them.

a talk on the linuxtag discussed this setup, and it scales
well to several ten thousand users, maybe several hundred
thousand users.

the other complexity i see is the problematic of sites:
usualy people work in one location, and companies
want to the file and mail storage servers at the same
location to save bandwidth. 

i want the simple server without sites first. so i wonder:
what is the largest company that does not need sites, or
what is the largest site a company could have?

so who is the biggest employer / site? only counting mail
users (not factory workers etc.). sap might be a good guess,
maybe 30k people near heidelberg? or some bank or insurrance
with maybe 50k people in one location?

you see, its hard for me to find any real world example except
internet server provider / web hosters who might need a system
scalable to millions of users. and those usualy design their own
systems anyway? i need to check back for current numbers, but
web hosters can serve a few million mailboxes with several high
end machines or one to two dozend normal linux server.

back to the concept level:
i prefer a simple setup with options as discussed above.
thus i don't want this domain setup. also discussions with
people running larger mail systems depending on ldap gave
me positive feedback, a template mechanism to dump ldap
information into config files is not necessary.

so, i wonder how big a simple mailsystem can get with options
as discussed above. i don't know. but i'm confident this approach
will be easy to understand and operate, and scale to a good level.

and if the concept reaches its limits, i guess it will be sites and
not pure user numbers or storage.

i don't want to stop you on your choosen course, and i hope
discussions about open source mail servers build on simpler
concepts are still welcome on this mailing list.

regards, Andreas