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  • Sizing

    Hello All,

    I Have to build a New network for 200 users with exchange and I wonder if there is some good guideline for how to calculate the server. They will be using a Citrix farm and the software supplier told me that there should be a max of 15-20 users per Server. So that will be 10 Citrix server (if budget is suff maybe one extra for maintenance/swap. But what about Exchange/DC Do you guys have any good exp or reference?

    a) how many connections can a DC handle (talking about eg an HP ML 370 2* 3.0 GHz Xeon CPU 4 GB RAM and Raid 1+0 72 for OS and Raid 1+0 72 for some files and printing

    b) What kind of Exchange server do I need?
    The server I installed never exceeded the 30 users.
    I think with 200 User you need Front and Back Server. But I dont want to risk of getting something that's "to small" So does the backend server be with 4 cpu's or can it be 2?

    c) The user will be roaming over the whole globe. They will be using OWA, but what if they enter a cyberbar in russia. how do I set the OWA to always use UK of France?

    d) One user now hasa mail box of 5 GB (uses pop3) and he is roaming the globe. How wil outlook (cached) perform? I Know its alot, but he is the boss and can mis any of his mail. He has his laptop and will be using or owa or http outlook. But how will replication behave?? does it work like the windows offline files?? that takes a while.

    If any Questions that can be answered would be great.

    Thanx in advance,

    [email protected]

  • #2
    Re: Sizing

    First of all.. You should implement IT policy in the company. For example, mailbox of 5 GB isnt something that user should use. SLA? What this size of
    users data in the next 5 years?
    There lots of sizing tips and there need for real life experience to plan
    I can gice a few guidelines:

    1. Exchange usually dont need more then 2 CPU's and 4 GB. For up to 50 users
    and 16 GB of storage 1 CPU can be use and 2 GB RAM.
    More then 50 users up to 200 can working with 2 CPU's and 4 GB,
    can support ~70GB storage without problem.
    You should buy HP Array 6404 with 256 MB Cache and setup two logical
    drivers with 15000 RPM Disks

    2. You should use Front\Backup or Back with ISA for RPC over HTTP, OWA etc.
    I dont like to give users even option to use POP3.
    Exch office should use its own Exchange routing group and server (dont
    forget to install GC + DNS in each office - can be use also as file server
    1 CPU, 2 GB RAM, HP Array 6404 with 256 MB Cache can support up
    to ~400 GB storage without a problem 2*74 GB 15000, 4*146 GB 15000 -
    There no logic to buy hard disks for users data less then 146 GB today).

    3. Citrix - There need to check the software/applications that need to run on it.
    Usually, 2 CPU's, 4 GB RAM, HP Array 6404 with 256 MB Cache and setup
    two logical drivers with 15000 RPM Disks.
    You will need to deploy to each office at least 2 Citrix with load balance
    (Citrix Advanced Server or Enterprise).
    For regular office use server can support up to 40-50 users without a
    If you are using CAD/Graphics, compiles etc. there may perfomance problem
    (it will be resloved in Citrix 5.0 and Windows Longhorn).
    Please remember that each year you should renew Citrix software.
    Also, I think that deploy to each office uniue Citrix farm setup in each
    office SQL server that can host the Citrix database and replicate the
    database from one site to another.

    Also, consider to use 1 GB Switchs (HP can do the work without extra price of
    Cisco) and buy HP Proliant 380 or HP Proliant 385 (You should use "Team"
    option in the network settings on the server). There no logical to buy
    tower server for office with more two servers.

    Backup - You should install at lease external HP LTO 200-400 Backup tape in
    each office. You can use Backupexec 10d.

    DRP - There need to create a DRP plan.

    Tip - Buy Windows 2003 R2 license if you can (The RTM should be release soon
    as I know).
    I hope that this tips can help you.
    Last edited by yuval14; 3rd December 2005, 17:08.
    Best Regards,

    Yuval Sinay

    LinkedIn:, Blog: