No announcement yet.

Exchange 2003 size and speed issues

  • Filter
  • Time
  • Show
Clear All
new posts

  • Exchange 2003 size and speed issues


    I have a client who has a high spec new server (8 cores, 16Gb ram, 4Tb storage), which acts as all things to them, DC, Exchange, VPN, File & Print. They're not a massive company, around 20 employees, but the amount of email they have is more than I've seen on average before.

    The largest have just over 9Gb of mail, the smallest 500Mb, with the average being around 3Gb. The main reason for this is they're a music label so sending 10mb attachments is that unusual. I've taught them how to send links internally rather than attachments, but externally they still need to attach, rather than using yousentit links or similar.

    In general, everything is working fine, they can connect, send/recieve fine, but every now and they get a freeze when a new mail arrives. From my investigations I can only point to the size of their mailboxes being the cause as when I cut one down to 200Mb (using a PST and reinitialising the OST), they didn't get the error.

    My question is 3 fold:
    1. Is their a max/recommended size fora mailbox on Exchange 2003?
    2. Are there any tips or tricks I can use to speed up Exchange (on the assumption the hardware isn't the issue)?
    3. Would there be a noticable performance increase by upgrading to a later version of Exchange (I've stuck with 2003 as I've not yet used 2007/2010)?



  • #2
    Re: Exchange 2003 size and speed issues

    There is no official note provided by Microsoft regarding the mailbox size but there are some articles refering to item count in critical folders. You can check the following link:

    Regarding tips and trricks for speeding up Exchange, the first and main tip would be, seperate Exchange on another machine. It's never a good idea to mix Exchange with other server tasks at the same machine specifically with DC functionallity.

    And of course there is a more then noticable performance jump while using Exchange 2007 or even better Exchange 2010. You can read about this all over the web.


    • #3
      Re: Exchange 2003 size and speed issues

      If the machine really has 16gb of RAM and has a single installation of Windows on it then you have a problem of too much RAM.
      Exchange 2003 can't cope with more than 4gb of RAM, and I have seen performance issues with that number. I never deploy Exchange 2003 with more than 2gb of RAM, and have had funny looks when I remove RAM, only to see the system stabilise.
      Therefore you will see a performance gain by removing RAM.

      If the resources are shared between multiple machines, then that will not be a problem.

      The bulk of performance issues with large mailboxes are down to the same thing - number of items in the folder. Try and keep things below 5000 items in any single folder. That isn't an Exchange issue, but an Outlook issue.

      The only other way to improve Exchange performance is storage. Storage, storage storage. Exchange is a high transactional database and if the storage is poorly configured then it will suck. Doesn't matter what you throw at it from a processor or RAM point of view.

      However with that amount of hardware, switching to Exchange 2010 on a 64 bit OS would allow the full resources to be used. Exchange 2010 does allow you to throw more RAM at it and it will see some benefit. However while you stick to Exchange 2003 it is wasted. Given what you have listed, I wouldn't have been able to justify more than 4gb of RAM on the box if there wasn't going to be a move to either VMs to split the roles up and/or to 64bit OS.

      Microsoft make no recommendations on the size of the mailboxes, never have done.
      The only recommendation they make is on the size of the information store, which in most cases should be between 50 and 100gb. However that is not a performance recommendation, but an SLA recommendation - ie the time it takes to recover the data in the event of a problem.

      Simon Butler
      Exchange MVP

      More Exchange Content:
      Exchange Resources List:
      In the UK? Hire me:

      Sembee is a registered trademark, used here with permission.