About CalDAV

[Helge Hess]

On 21. Jan 2005, at 23:05 Uhr, Martin Konold wrote:
> Actually for typical use about 98-99% of the servers cycles are spent 
> on
> dealing with emails not calendars, contacts or tasks.

It would be interesting to see the setup you used to determine those 
numbers! Or might it be possible that this is just a claim without 
factual underpinnings? ;-)

> There are really big installations with up to more than 10k 
> _concurrent_ users
> and more than 250k user mailboxes.

I didn't ask about Cyrus mail server installations, I asked about 
_Kolab_ installations - that is, installations which use the Kolab 
variant of the server _and_ the Kolab variants of the clients (either 
Outlook+Connector or Kontact).
Kolab is not just mail, otherwise it would be superflous ;-)

To quote myself:
---snip---
No offense, but is there any actual Kolab user which has more than 500 
seats doing calendaring on a single server? I think not.
---snap---
Why don't you just answer my question and instead move the discussion 
to an entirely different topic. Interesting.


Fact is, you have yet to prove that the concept actually works/scales 
for calendaring, tasks and contacts. You claim that you inherit the 
scalability advantages of mail for those applications of the IMAP4 
protocol, but so far there is no evidence that this actually works - 
nor the contrary of course.
Claiming scalability to 250.000 users when you don't even have an 
installation for 1.000 users is, well, adventurous at best.

How do you perform load balancing tests on your servers? (I hope you do 
perform scalability tests to test your concept, um, no?)

> The CMU people report that on a old Sun Ultra 80 (4x450MHz Ultrasparc 
> 2) with
> 4GB memory they could support 6200 _concurrent_ users which effectivly 
> leaves
> about 600KB of Memory per concurrent user.

Yes, for mail which is heavily single user and - more importantly - 
strictly read only. We know that mail/IMAP4 scales very well and this 
is why almost every groupware project - including OGo - uses Cyrus as a 
mail server.

> How many concurrent users can whatever version of Opengroupware 
> support on a
> 4GB machine?

For mail? Obviously the same amount since we use Cyrus for mail too. 
What is your largest installation for _calendaring_, that is, the 
application of your "Kolab concept"?

BTW: your attacks on OGo are inappropriate. We are not the ones who 
claim being superior in scalability! The current OGo server is build 
with focus on depth of functionality, not for scalability. Yet despite 
the fact that OGo is not built with raw scalability in mind, you fail 
to show a single Kolab installation which is even near the size of 
regular OGo ones and proves your concept. Kind of weird, isn't it? ;-)


Keep cool, just asking questions ;-)

Greets,
   Helge
-- 
http://docs.opengroupware.org/Members/helge/
OpenGroupware.org