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  • Exchange Server Sizing.

    All -

    I'm working on a sizing a new exchange server but need documented evidence suggesting the benefit of separating the exchange logs onto its own RAID controller in a RAID1 config as opposed to locating the logs and the databases on the same RAID10 array.

    The config i have now set is:

    Single RAID card

    RAID - 1 - OS

    RAID -1 - LOGS

    logical partitions separating above.

    Separate RAID card

    RAID 10 - databases

    8 146 gb 10k SAS drives in total.

    8gb DDR2 MEM.

    Ideally, i'd probably put SMTP quues and exhange temp onto its own RAID1 array as well, but budget doesn't allow us to get this done.


    I found this article:

    Are there others ?




  • #2
    Re: Exchange Server Sizing.

    This has been the case since Exchange was first released.

    Exchange is basically a high transactional database, which is making sequential writes to both the logs and the database.

    This section on Technet should give you everything that you need: http://technet.microsoft.com/en-us/l.../bb124518.aspx

    If you use the Storage Calculator from Microsoft it will also show seperate storage for the logs and the database.

    Simon.
    --
    Simon Butler
    Exchange MVP

    Blog: http://blog.sembee.co.uk/
    More Exchange Content: http://exchange.sembee.info/
    Exchange Resources List: http://exbpa.com/
    In the UK? Hire me: http://www.sembee.co.uk/

    Sembee is a registered trademark, used here with permission.

    Comment


    • #3
      Re: Exchange Server Sizing.

      Thanks for the link Simon.

      However, i don't see anything mentioned about separating the log files on that page. I'd like for management to read it from Microsoft or a trusted source then just believing what i have to say..

      any others ?

      Thanks again.

      Comment


      • #4
        Re: Exchange Server Sizing.

        Did you read all of that SECTION?

        "For performance and recovery reasons, it has always been critical to separate transaction log files from the database files at both the LUN and physical disk levels."

        It is on the Mailbox Store size section.

        Simon.
        --
        Simon Butler
        Exchange MVP

        Blog: http://blog.sembee.co.uk/
        More Exchange Content: http://exchange.sembee.info/
        Exchange Resources List: http://exbpa.com/
        In the UK? Hire me: http://www.sembee.co.uk/

        Sembee is a registered trademark, used here with permission.

        Comment


        • #5
          Re: Exchange Server Sizing.

          Apologies Simon, i didn't get to that page.

          Thanks for the tip.

          Comment


          • #6
            Re: Exchange Server Sizing.

            Simon -

            I'm configuring an HP server, specfically a DL380 G5, for the first time as my exchange server.

            I understand HP can create disk array's then from a single raid controller you can configure logical RAID sets from this disk array, for example:

            8 drive disk array

            2 drives - RAID1 - OS

            2 drives - RAID1 - Transaction logs

            4 drives - RAID10 - Exchange databases

            All on one RAID card.

            Is this a recommended practice on a hardware side for Exchange ? Or should i configure two separate disk arrays and two separate RAID controllers ?

            4 disk array

            RAID1 - OS

            RAID1 - Logs

            4 disk array

            RAID10 - Exchange databases

            Comment


            • #7
              Re: Exchange Server Sizing.

              If you have the option to do so, I'd opt for separate RAID controllers. This isn't something you want to cut corners on.
              Gareth Howells

              BSc (Hons), MBCS, MCP, MCDST, ICCE

              Any advice is given in good faith and without warranty.

              Please give reputation points if somebody has helped you.

              "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

              "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

              Comment


              • #8
                Re: Exchange Server Sizing.

                On smaller sites I have put everything on to a single card. Often I will try and get a slightly faster card if possible.
                With larger sites, dual cards are really best. The OS and the logs can share a card quite happily (they can even share an array in separate partitions on low traffic sites).

                The key is to have the t-logs and database on separate arrays at least, for performance reasons. You also want the logs in at least a different partition from the OS. That is not for performance, but in case something goes wrong. Trying to get a server with zero space to boot is painful at best. By having the logs in their own partition or array, there is a limit to how much space they can take up.

                Simon.
                --
                Simon Butler
                Exchange MVP

                Blog: http://blog.sembee.co.uk/
                More Exchange Content: http://exchange.sembee.info/
                Exchange Resources List: http://exbpa.com/
                In the UK? Hire me: http://www.sembee.co.uk/

                Sembee is a registered trademark, used here with permission.

                Comment


                • #9
                  Re: Exchange Server Sizing.

                  Thank You.

                  Right now, i'm getting 2 RAID cards.

                  However how should i configure the disk array for the OS and Logs ?

                  I'll have 4 disks and originally i was thinking about creating two RAID1 sets ( this will present two disks to windows, correct ? C, D ) S

                  I've never setup an HP disk array before and just curious what's the optimal setup.

                  Comment


                  • #10
                    Re: Exchange Server Sizing.

                    You have four disks for the OS and logs, or 4 disks in total?

                    If you have four disks for the OS and logs, then put all four on the same card, and create two mirror arrays. HP servers come with a quick start CD, use that and it will do everything for you, including installing Windows.

                    Then put the disks for the database on its own card exclusive. Again use the HP tools to create the array. Each array will appear to Windows as a single disk.

                    Simon.
                    --
                    Simon Butler
                    Exchange MVP

                    Blog: http://blog.sembee.co.uk/
                    More Exchange Content: http://exchange.sembee.info/
                    Exchange Resources List: http://exbpa.com/
                    In the UK? Hire me: http://www.sembee.co.uk/

                    Sembee is a registered trademark, used here with permission.

                    Comment


                    • #11
                      Re: Exchange Server Sizing.

                      RAID 1 is fine for the OS and the logs, but I would recommend that you use RAID 5 (or as you suggested earlier, RAID 10) for the data.

                      Also keep in mind that ideally you don't want to have the data partition more than 50% full during general usage - the Microsoft documentation for recovering Exchange using Recovery Storage Groups states that you should ensure at least 50% is free. Whether most Exchange servers actually *do* have that much free or not...
                      Gareth Howells

                      BSc (Hons), MBCS, MCP, MCDST, ICCE

                      Any advice is given in good faith and without warranty.

                      Please give reputation points if somebody has helped you.

                      "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                      "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                      Comment


                      • #12
                        Re: Exchange Server Sizing.

                        I'm going to have a total of 8 drives, but I convinced management to get 2 RAID cards.

                        Since i never setup disk array's before ( Dell's don't do disk arrays, at least the servers i've setup) I'm still curious on how to set that up. The setup disk setup sounds just like what Dell's does as well.

                        So as i'm setting up the HP box, i would create 2 disk arrays ?

                        1 array with 4 disks ? with two RAID1 arrays.

                        1 array with 4 disks ? with one RAID10 array

                        This would be done before the OS, i assume ?

                        Comment


                        • #13
                          Re: Exchange Server Sizing.

                          Yes, this is done before installing the OS. Usually, after the system POSTs and you see "Press Del to enter Setup" (don't enter the BIOS, allow it to continue booting), it will display something like "Press <keys> to enter RAID setup". Enter the RAID controller's BIOS and setup the arrays in there.

                          On the data array, configure one of the drives as a hot spare. Most RAID implementations allow you to carry on working after a drive failure, but if you have a hot spare then you won't lose redundancy.

                          Refer to the documentation for your RAID controller for details on how to configure it, as this will vary.
                          Gareth Howells

                          BSc (Hons), MBCS, MCP, MCDST, ICCE

                          Any advice is given in good faith and without warranty.

                          Please give reputation points if somebody has helped you.

                          "For by now I could have stretched out my hand and struck you and your people with a plague that would have wiped you off the Earth." (Exodus 9:15) - I could kill you with my thumb.

                          "Everything that lives and moves will be food for you." (Genesis 9:3) - For every animal you don't eat, I'm going to eat three.

                          Comment

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