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Joe · Guest

All of the current whitepapers are geared towards perf and capacity planning
for MAPI users. I need help with how to design the servers and storage for
about 50,000 users that will be regulated to just OWA, POP and IMAP. Anyone
have any ideas?

Mark Arnold [MVP] · Guest

On Mon, 27 Jun 2005 11:44:57 -0500, "Joe" <joe@do.not.email.me> wrote:

Al Mulnick · Guest

Do you have more information available?

Storage: Do you intend for POP users to store mail locally only? Or locally
and on the server? What is the mailbox sizing you're aiming for?
Usage patterns: Is this all in the same time zone with all users
concurrently using the system? If not, how many concurrent are expected?
Message size: What's the average message size you expect?

Generally speaking, SMTP performance is achieved by adding physical disks
especially for submit transactions. Delivery will also have some disk
performance relationship.

POP, IMAP, and HTTP users typically scale quite well and are what the FE/BE
scenario is designed to achieve. My biggest concern in that kind of design
would be around reliability (availability of service) and disk subsystem.
Network topology would be next depending on the requirements.

Al

"Joe" <joe@do.not.email.me> wrote in message
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Joe · Guest

Thanks, I'll look on HP's site for it.

"Mark Arnold [MVP]" <mark@mvps.org> wrote in message
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Al Mulnick · Guest

In the end, you're trying to size for latency of the system over space
concerns.

FWIW, the mapi assumption assumes you will NOT be downloading all messages
at the same connection although with cached mode and OST you certainly could
do the same. In planning for mapi clients, the excpectation is that you'll
download the mail items you want and delete the ones you don't based on the
information presented. Also, you won't be checking email every five -
fifteen minutes, but instead would be notified of new mail if using mapi
(actually that depends on the client version, but for planning purposes,
that is usually the case.)
POP/IMAP utilizes a polling mechanism as does OWA (last I checked anyway).
SMTP is send when told to send or as configured.

Polling intervals can be changed depending on the UA, so I'd say you should
plan for the worst case possible if performance is important. So if the
usage pattern is 99% in the same timezone and possibly with the same usage
schedule (I typically plan around the the 80-10-10 usage rule: 80% will be
online at the same time(s), 10% will be on vacation and not checking email
at all and 10% will be going nuts and checking mail every 10 seconds.) then
you should plan to support the same or higher workload for the DB's but this
is entirely dictated by the UA usage pattern that is going to be unique to
your facility.

POP clients, by default will download their mail on connect. That's a
bigger hit than just downloading the headers and would be on par with cached
mode clients which do the same things. OWA clients, if they use the default
layout, download the message they're looking at and the headers + 2 lines of
the email messages in the inbox to present to the web client, but because
it's stateless, it can absorb a lot more latency than POP or IMAP before the
client will notice anything.

If anything, I would structure my BE db's to handle the downloads expecting
the worst regardless of UA type. If that's not possible, I would suggest a
pilot to allow you to figure out how your usage patterns are going to look.

I think mapi in this case is not as important to your BE server sizing for
what it's worth, especially if you plan to leave the mail on the servers.
Keep in mind that as your mailstore grows, the impact to downloading and
delivering etc becomes more dependent on the disk (more area to cover as it
grows). That indicates spindles are more important than space.

FE servers will likely scale well for that design with minimal hardware.

Al

"Joe" <joe@do.not.email.me> wrote in message
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Joe · Guest

-We would give the users' the option to store all mail locally or on the
server. Most tend to leave mail on the server.
-No quota as planned (yes I know it's tough to design without any quotas.)
-99% are in the same time zone.
-Most messages are in the 10-50KB range.

Though I will need to look into planning the SMTP servers, my biggest
concern is the spindle count for the DB's at this point. The current
whitepapers go over calculating the IO's per average user and how to design
your storage. I was at Teched this year and the guys I spoke with didn't
really have an answer for IO's for an average OWA, POP and IMAP user. We
all agreed it was less but I need a definitive answer. The previous post
talked about the HP sizing tool which I'm going to look at.

"Al Mulnick" <amulnick_No_SPAM@ncDOTrr.com> wrote in message
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