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  1. #1
    Join Date
    Jul 2010
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    3

    Unanswered: MS SQL Server Hardware

    Hi all,

    I was looking for input on RAID configurations for an MS SQL 2008 database server.

    We will be going 15k SAS Drives, and either (6) 3.5in drives, or (8) 2.5in drives.

    Any input is appreciated.

    Thoughts on:

    6 3.5in SAS Drives in following config:

    RAID 1: OS
    RAID 10: MS SQL Data/Log

    6 3.5in SAS Drives in following config:

    RAID 1: OS
    RAID 1: SQL Data
    RAID 1: SQL Log


    or

    8 2.5in SAS Drives in following config:

    RAID 1: OS
    RAID 10: SQL Data
    RAID 1: SQL Log



    Obviously the cheaper option is the six 3.5in drives, which would get us more space as well because 3.5in 146GB drives cost the same as 2.5in 73GB SAS drives.

    If we went the 3.5in disks would you prefer 3 RAID 1s, or RAID 1 for OS and RAID 10 for All SQL Data/Logs.


    Thanks!

  2. #2
    Join Date
    Jul 2003
    Location
    San Antonio, TX
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    3,662
    Some critical pieces of info are missing here. The biggest one is: What is the server for?

    It also seems like a trend, that when talking about 2K5 and up, people completely forget about tempdb, which is the 1 ultimate bottleneck.
    "The data in a record depends on the Key to the record, the Whole Key, and
    nothing but the Key, so help me Codd."

  3. #3
    Join Date
    Jul 2010
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    3
    It's an MS SQL 2008 Database server that powers a few ASP.NET web applications. (built on Community Server and Dot Net Nuke)

    TempDB is another issue, where would it go on any of those RAID configurations?

  4. #4
    Join Date
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    I imagine Robert was thinking about dedicated drives for tempdb, but if those are your only options then don't treat it differently to the other databases.
    "best" would be option 3, but depends on your actual need as Robert says. It might not be necessary to spend the extra money if these are low throughput sites.
    Testimonial:
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    ur codings are working excelent.

  5. #5
    Join Date
    Jul 2010
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    These are not low throughput sites. Pushing 60mil page views a month, very DB intensive applications.

    If we had to go with the six 3.5 in drives and were not able to do the RAID1/RAID1/RAID10 what do you think would be best?

    RAID 1: OS
    RAID 1: Data
    RAID 1: Log

    RAID 1: OS
    RAID 10: All SQL Data / Log

    Thanks guys.

  6. #6
    Join Date
    Jul 2003
    Location
    San Antonio, TX
    Posts
    3,662
    I know you wouldn't like it, but it does depend. It depends on whether you'd consider at least a NAS, if not a small SAN for your box. It sounds like the data consumers will be working against OLTP databases as well as generate reports. These are 2 dramatically different environments, which means the server configuration should tailor to each in a different way. At the very minimum each database needs to be configured differently. And when talking about tempdb (see the very first sentence), - it also needs to be configured differently for OLTP vs. reporting databases.

    For OLTP databases it can be left at default settings, 1 file for each device type.
    For reporting (DSS or DW/DM's) it better be configured to account for multi-threaded parallel processing, but a true one, not like MS recommends, - count CPU's, close your eyes, and create as many MDF's as there are CPU's, and it doesn't matter if all files reside on the same disk. In order to truly be able to support reporting requirements, and take full advantage of the multi-processor environment, you need to ensure that IO requests are also channeled independently from each other. This means that for each pair of IO requests you must have either 2 logical drives comprised of RAIDed physical drives on 2 different controllers, or at least on 2 different channels of the same controller.

    Having said that, - do the count, and see if you really need 6 or 8 local drives, or maybe a NAS...
    "The data in a record depends on the Key to the record, the Whole Key, and
    nothing but the Key, so help me Codd."

  7. #7
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    Feb 2004
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    You would only have data and logs on the same drive for noddy databases.
    Testimonial:
    pootle flump
    ur codings are working excelent.

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