AW: [imp] Scalability of IMP

[Ramon Kagan]

HI,

I'm running the following configuration for 40,000 users, soon to be
50,000.  We send anywhere from 3000-5000 messages a day, handling between
600,000 and 900,000 requests.  Response time for login, inbox retrieval
(using imap) and sorting has a 75th percentile about 3-4 seconds with
inboxes ranging from 100 kB to over 250 MB, and messages counts from as
low as 5 to over 10,000.

2 - LVS directors for High Availability load-balancing
	PII 333, 64 MB RAM, 100 Mb FD NICS

3 - Horde machines
	Dual  PIII 866, 1.5 GB RAM, 100 Mb FD NIC

Postoffice Cluster:

3 Sun Ultra 5
1 Sun E220R
1 Dual PIII 1.3, 4 GB RAM, 100 Mb FD NIC

Data resides on a Net App Filer 760 with Gb NIC

Note that we will be upgrading this structure as follows, since the
actually bottleneck in our system is the postoffice and Net App Filer.

2 - LVS directors for High Availability load-balancing
        PIII 550 or higher, 256 MB RAM, 100 Mb FD NICS

5 - Horde machines
        Dual PIII 866, 1.5 GB RAM, 100 Mb FD NIC
	Dual PIII 1.4, 2 GB RAM, Gb FD NIC

Postoffice Cluster:

1 Dual PIII 1.3, 4 GB RAM, 100 Mb FD NIC
4 Dual PIII 1.4, 2 GB RAM, Gb FD NIC


Data will reside on a Net App Filer 840 with Gb NIC


Simulations show that the 75th percentile response time should lower to
the 1-1.5 second range, and for the resource pigs (huge inbox and message
count)  response time should drop significantly.

This may be overkill, depending on the mandate for you response.  Our
executive have mandated response times to be under 8 seconds for overseas
usage.  Taking into account a 4 second delay for oversea network travel,
this makes the requirement for such powerful machines.

Ramon Kagan
York University, Computing and Network Services
Unix Team -  Intermediate System Administrator
(416)736-2100 #20263
rkagan@yorku.ca

On Thu, 6 Jun 2002, Kuhl, Oliver wrote:

> > > What hardware do I need?
> >
> > What hardware do you have? What software do you use? Please describe your
> > "little testinstallation" in more detail.
> My little Testinstallation is a Pentium 300 with 128 Mb RAM running debian
> linux. I'm using the IMAP-Servers of my company, which are highly scalable
> and currently serve about 100,000 users. Now I want to find out what
> hardware I need for the webmail-server, which should run debian or solaris
> with apache, php and mysql. Maybe I have to built a server-farm, or I need a
> dual cpu machine. That has to be found out....
>
> Regards,
> 	Oliver.
>
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