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Exchange database cache, IOPS and memory

    Question

  • I'm attempting to determine memory needed beyond the 10 GB required for an Exchange 2010 server holding the CA, HT and MB roles

    This is the document I am using:

    http://technet.microsoft.com/en-us/library/ee832791.aspx

    In particular, I'm trying to articulate the relationship between the Exchange database itself and the database cache.

    With a 64 bit OS, you can "increase the database cache".

    This sounds like a good thing but what does it mean exactly?

    Can all or part of the database simply be loaded into memory (which would provide faster access than having to access disk)???

    Otherwise,let's say we have 100 mailboxes with the following message profile: 50 messages per day (send/receive), average size 75 kb

    I should allocate 6 MB per mailbox for the database cache (600 MB) and at 0.120 IOPS per mailbox, plan for 12.0 IOPS (single database copy).

    Does that look right?


    Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.

    Sunday, April 01, 2012 4:51 PM

Answers

  • Not items, but database blocks that have been accessed.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

    Tuesday, April 03, 2012 5:37 AM
  • But would it be correct to say that Exchange loads all or part of the database in memory?


    It doesn't load the entire database into memory, although I guess it is possible if the DB is small enough and *everything* got accessed. It caches recently used items and 'views' by the end users to make sure client refreshes are fast.

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Tuesday, April 03, 2012 2:26 AM

All replies

  • The more memory you put in an Exchange mailbox server the more it will use to cache mailbox data, and therefore optimize disk I/O.

    For 100 users, you really don't need to sweat the memory too much.  Install 16GB and you'll be just fine.


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

    Sunday, April 01, 2012 7:56 PM
  • Go no further than here...

    http://gallery.technet.microsoft.com/Exchange-2010-Mailbox-Server-Role-/


    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Sunday, April 01, 2012 11:00 PM
  • Thanks guys, those are both helpful.

    But would it be correct to say that Exchange loads all or part of the database in memory?

    If not, what is being cached? Most frequently or recently used items (messages, calendar... ?).


    Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.

    Tuesday, April 03, 2012 12:49 AM
  • But would it be correct to say that Exchange loads all or part of the database in memory?


    It doesn't load the entire database into memory, although I guess it is possible if the DB is small enough and *everything* got accessed. It caches recently used items and 'views' by the end users to make sure client refreshes are fast.

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Tuesday, April 03, 2012 2:26 AM
  • Not items, but database blocks that have been accessed.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

    Tuesday, April 03, 2012 5:37 AM
  • Well yes, but I didn't think we were going Level 300+ in this thread. :)

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Tuesday, April 03, 2012 11:05 PM
  • Only 300+ level because of inflation.  That used to be 200- level.


    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

    Wednesday, April 04, 2012 2:04 AM
  • What are you guys talking about? Are those escalation levels or something like that?

    Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you.

    Wednesday, April 04, 2012 2:11 AM
  • LOL!!!

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Wednesday, April 04, 2012 2:13 AM
  • We tend to use level, 100, 200, 300, 400 typically as detail levels when discussing Exchange or any other teachable topic with 100 being entry level with high level overviews and 400 being expert/verbose level detail down into the depths of exactly how everything works behind the scenes.

    Microsoft Premier Field Engineer, Exchange
    MCSA 2000/2003
    MCTS: Win Server 2008 AD, Configuration MCTS: Win Server 2008 Network Infrastructure, Configuration
    MCITP: Enterprise Messaging Administrator 2010
    Former Microsoft MVP, Exchange Server

    NOTICE: My posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

    Wednesday, April 04, 2012 2:14 AM