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  • recommendations setting up RAID5 partitions...

    I've seen a few suggestions while google'n around. Many state to have 3 partitions...such as

    1. System OS (100gb)
    2. Exchange Data Files (100gb)
    3. All other Data Files (150gb)

    but offer really no reason or logic. I'm going a straight Raid5 across the board with 6x73gb drives. I've learned in the past you can never have to much space considering our first servers with Win2K went almost 7 years...and a lot of growth occurred in 7 years!

    What is good or bad with having two partitions such as:

    1. System OS
    2. (Data) Everything else (250gb) (exchange mbx, user data, shared data, sharepoint, wsus)

    I understand that the number and size of exchange mailboxes defines the size of the partitions to set.

    What is the big advantage to having the exchange files on a separte partition rather then sharing the same partition with user data, WSUS, etc?

    It's all the same raid5 and I would think I'd have more room to grow if I don't limit the exchange partition.

  • #2
    Re: recommendations setting up RAID5 partitions...

    I beleive best practice is to usually separate Logs and Databases, both for SQL and Exchange
    However, that usually refers to even separate platters where possible.

    Think of it this way. If a user is somehow able to generate a massive 200GB file, that could affect your exchange database if it can't grow when it needs to..
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    • #3
      Re: recommendations setting up RAID5 partitions...

      Originally posted by tehcamel View Post
      I beleive best practice is to usually separate Logs and Databases, both for SQL and Exchange
      However, that usually refers to even separate platters where possible.

      Think of it this way. If a user is somehow able to generate a massive 200GB file, that could affect your exchange database if it can't grow when it needs to..
      That makes good sense if I users are not given quotes on personal folders/shares and how they could mess up the exchange needs.

      Thank you.

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      • #4
        Re: recommendations setting up RAID5 partitions...

        Do you want to cripple this machine out of the box?
        As that is what you are going to do if you configure it with a single RAID 5 drive.

        RAID 5 is slow, very slow. Partitioning it does nothing for performance.
        Storage is cheap, you can get a NAS box to sit on the network to store files and stuff.

        Usually I would say to configure 2x drives as RAID 1, but I notice that you have 2x 73 gb drives. That isn't going to give you enough space, as SBS 2008 will refuse to install with less than 80gb of space. Even that will be tight.

        Any chance of sending the drives back and getting something larger? I wouldn't have bought this machine for SBS 2008 personally, because of the limitations on the drive configurations.
        To be blunt - the server you have you will outgrow in months, simply because its performance will be very very poor, right from the start.

        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.

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        • #5
          Re: recommendations setting up RAID5 partitions...

          I appreciate your comments and although your theory maybe true on paper with raid5 being slower then raid1, I don't think real work is true in our case. Since you don't know what our server is doing, how many users, ect...it's just a best practice theory IMHO. In your applications it may be perfectly true.

          Until 3 years ago we were still running older dell P3 (800mhz) with raid5 an never had any preformace issues with disk write/read...as a matter of fact I built a new file server for testing last year with 7500 rpm SATA in raid 1 and was amazed that disk reads seemed slower then our older P3 raid5 server.

          So crippling is a strong choice of words when we are talking small units of time.

          If we had heavy application servers that were taxed but larger number of users...changes are SBS wouldn't be our choice.

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          • #6
            Re: recommendations setting up RAID5 partitions...

            Unless you are running a very very small number of users (less than 10) RAID 5 will be slow.
            RAID 5 works best for READ, not WRITES. I have seen too many systems with RAID 5 where the performance has been very very poor, even with a small number of users.

            There is an awful lot of writing going on constantly. Remember Exchange is WRITING to two places at the same time, which means if you have a single RIAD 5 array, you are causing two bottlenecks, the slow speed of RAID and the dual writes at the same time. That doesn't even take in to account the other writing that SBS is doing - it has a number of SQL databases for example.

            If you have been running RAID 5 for some time, then you may well feel that the performance you have seen is acceptable.

            Partitions will do nothing for you. You may as well put everything in to a single partition.

            I have provided my opinion, which you have opted to dismiss, as is your choice.

            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.

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            • #7
              Re: recommendations setting up RAID5 partitions...

              simon,

              You mention RAID5 as being slow in terms of high-utilisation exchange databases. What would you personally recommend to clients normally?
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              • #8
                Re: recommendations setting up RAID5 partitions...

                Personally I would recommend using mirror sets for OS, an additional set for Logs and a Third set for the database.
                Or rather raid 0+1 (or was it 10. I always forget the difference ) for the database.

                And where possible on separated controllers.
                Marcel
                Technical Consultant
                Netherlands
                http://www.phetios.com
                http://blog.nessus.nl

                MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
                "No matter how secure, there is always the human factor."

                "Enjoy life today, tomorrow may never come."
                "If you're going through hell, keep going. ~Winston Churchill"

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                • #9
                  Re: recommendations setting up RAID5 partitions...

                  You can get away with RAID 5 for the Exchange database only, and I have done so on many occasions. The performance impact doesn't make a massive difference unless you are under a very heavy load.

                  The point I was making was that what you do NOT want to do is put both the transaction logs and the database on to the same array.

                  For maximum performance, everything on mirrors is the best way forward, but that can often mean lots of arrays and lots of disks.

                  I recently built a server that contains NINE mirrors using 18 disks. All pairs, one for the OS, then two sets for each database (so one mirror for logs, one mirror for databases). The server is under very heavy load (900 users, a third with Blackberry), but screams along with no bottlenecks.

                  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


                  • #10
                    Re: recommendations setting up RAID5 partitions...

                    Yes, you can get away with a Raid 5 system however a while ago I read a document at the Microsoft website where they recommended a Raid 10 (0+1). This was also recommended by HP.
                    I have to admit this was with Exchange 2003 but since the database hasn't changed a lot... Anyhow the reason of not using Raid 5 was that this mechanism had more write actions which could reduce the performance.

                    However I never really noticed any degredation, but yes we kept the logs separated on a different array which would also be my advice.
                    Marcel
                    Technical Consultant
                    Netherlands
                    http://www.phetios.com
                    http://blog.nessus.nl

                    MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
                    "No matter how secure, there is always the human factor."

                    "Enjoy life today, tomorrow may never come."
                    "If you're going through hell, keep going. ~Winston Churchill"

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                    • #11
                      Re: recommendations setting up RAID5 partitions...

                      Was that article sponsored by a major HDD manufacturer?
                      (Simple -- 3 drive -- RAID 5 = 3 writes + 1 parity calculation for 2 blocks, simple -- 4 drive --RAID 10 = 4 writes for 2 blocks)
                      Yes, I know it is not quite as simple as that in the real world, but you sometimes wonder about all this advice that expects you to add yet more drives, then more power, then a larger enclosure....

                      <ontopic> as already said, keep the logs and dbs on separate arrays, not just for speed but also for redundancy
                      Tom Jones
                      MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
                      PhD, MSc, FIAP, MIITT
                      IT Trainer / Consultant
                      Ossian Ltd
                      Scotland

                      ** Remember to give credit where credit is due and leave reputation points where appropriate **

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                      • #12
                        Re: recommendations setting up RAID5 partitions...

                        Tom, I removed a bit from the table to make it more readable though here a link from ms:
                        http://technet.microsoft.com/en-us/l.../ee832792.aspx
                        supported/best practices
                        OS/System/Pagefile Volume
                        All RAID types supported.
                        Best practice: RAID 1/10.

                        Exchange Mailbox Database File (EDB) Volume
                        All RAID types supported.
                        Best practice: 5,400/7,200 disks = RAID1/10 only.

                        Exchange Mailbox Database Log Volume
                        All RAID types supported.
                        Best practice = RAID1/10.
                        But the bottom line separate logs from de DB
                        Marcel
                        Technical Consultant
                        Netherlands
                        http://www.phetios.com
                        http://blog.nessus.nl

                        MCITP(EA, SA), MCSA/E 2003:Security, CCNA, SNAF, DCUCI, CCSA/E/E+ (R60), VCP4/5, NCDA, NCIE - SAN, NCIE - BR, EMCPE
                        "No matter how secure, there is always the human factor."

                        "Enjoy life today, tomorrow may never come."
                        "If you're going through hell, keep going. ~Winston Churchill"

                        Comment


                        • #13
                          Re: recommendations setting up RAID5 partitions...

                          I am going to add my 2p worth here.
                          This talk of "best practices" is usually fine for the enterprise, but doesn't usually scale down to the "S" side of SMB. IMHO, SBS2008 is already expensive enough for those in the 5-15 user bracket, and to add the hardware requirements of 3 Mirrors or RAID10 just wont fly economically. Sure Hardware has come down in price and disk space is cheap, but an entry level server which ran SBS2003 fine just doesn't have the capacity for that number of disks to be attached. Also, to start adding NAS and SAN just adds complexityto the management in a small office.
                          Another point is I feel Microsoft wants to push Hosted Exchange as much as it can. So as well as disk manufacturers having an interest in skewing the figures, I feel Microsoft has a similar interest to push the SMB to Hosted Exchange. I know that for a number of my customers, hosted exchange would make sense, but others are simply not able to because of LOB or Security/Privacy/Regulatory concerns.
                          In conclusion, I would say, get a box with 12-16GB RAM, 5 disks (if you can). Mirror the first two for the OS (and as has been rightly said, >80GB) and make RAID5 out of the other three. They will hold your Exchange databases AND logs, your SQL databases AND logs and all your file shares.
                          If you have an LOB application requirement, go for Premium and put that app + SQL there - an entry level machine will do and a pair of mirrored 250 or 500GB SATA disks. Add another pair of mirrored disks to it if the budget allows.
                          Finally, if the business owner doesn't want all that Hardware "lying" around his office, get something like an HP ML380 with lots of stuff and virtualise the two servers on banks of mirrored disks.
                          None of this may be the fastest, but it will work satisfactorily for 5-15 users and keep the business owner happy with the expenses.
                          (PS this should have been a blog, but no-one would read any blog I wrote!)
                          TIA

                          Steven Teiger [SBS-MVP(2003-2009)]
                          http://www.wintra.co.il/
                          sigpic
                          Iím honoured to have been selected for the SMB 150 list for 2013. This is the third time in succession (no logo available for 2011) that I have been honoured with this award.

                          We donít stop playing because we grow old, we grow old because we stop playing.

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