Disk/RAID setup with limited disks for Windows 2008 R2 and SQL 2012

  • I am wondering what would be the best disk/RAID setup for a Windows server 2008 R2 OS and SQL Server 2012 database that has heavy read/write. I have the following disks I can use:

    4x 15k 146GB

    2x 10k 600GB

    According to the server build requirements for the application, I need 100GB for the OS and 290GB for the drive containing the SQL mdf there are no stated requirements for the ldf, but would like to know if it should be allocated elsewhere?

    I'm not sure whether I should do RAID 10 for the 15k drives for SQL and RAID 1 for the OS on the 10k.

    Any help would be greatly appreciated.

    Cheers

  • andrew_king (6/27/2015)


    I am wondering what would be the best disk/RAID setup for a Windows server 2008 R2 OS and SQL Server 2012 database that has heavy read/write. I have the following disks I can use:

    4x 15k 146GB

    2x 10k 600GB

    You're pretty limited here with your options.

    andrew_king (6/27/2015)


    According to the server build requirements for the application, I need 100GB for the OS and 290GB for the drive containing the SQL mdf there are no stated requirements for the ldf, but would like to know if it should be allocated elsewhere?

    The sql server data files and log files must be separated to ensure good performance.

    You need to consider where backup files will be read\written these have their own I\O requirements too.

    andrew_king (6/27/2015)


    I'm not sure whether I should do RAID 10 for the 15k drives for SQL and RAID 1 for the OS on the 10k.

    Any help would be greatly appreciated.

    Cheers

    For 2 drives RAID1 is pretty much the only fault tolerant option, you need 3 or more disks to start employing higher RAID levels.

    RAID10 on the remaining disks will only provide half the capacity. A RAID5 array will provide good read performance with a write penalty and offer higher space utilisation.

    Is there no option of increasing the disk\spindle count?

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  • Thanks for your response!

    I do have access to other 600GB 10k drives (9 more to be exact). But there is application storage I have to take into consideration and was planning to use those drives in a RAID 5 for the applications specific storage (very large files that grow everyday).

    I could perhaps use 1 or 2 more of those disks, so could provide:

    4x 146GB 15k

    3 or 4 x 600GB 10k

    I guess my greatest concern is if there is significant performance hit on having 10k drives for this solution, and which model to deploy based on what I have, for example, better to have OS and ldf on the same 15k disk group, with a RAID for the 10k to house the mdf?

    Cheers!

  • I recall that the 15k drives have a seek time around 2.5ms, and the 10k drives around 4ms, so there is a penalty. I hope your server has a lot of memory - preferably 128GB for a Standard license, so SQL Server can cache your data. You can cripple performance despite fast drives with too little memory.

    I would put the OS and stable application software on a RAID-1 pair, and use the second pair of 146GB drives for database logs and tempdb. All of the 600GB drives can be a RAID-5 set, holding the database and backups (compressed). Be sure to do transaction log backups frequently to control the size of your LDF. Another option is to split the database between active tables on the 146GB RAID-1 set, and the rest on the slower RAID-5 set. You should find that performance after the cache is warmed up should be pretty good.

    Good luck -

    Alan

  • Standard edition of sql server 2012 only supports 64GB RAM, for 128GB you'll need Enterprise or install SQL Server 2014 Standard edition

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    "Ya can't make an omelette without breaking just a few eggs" 😉

  • True, but after Windows, other services, and your application are cooking you may use considerably more then 64GB. My production server, running SS12SP2 Standard with 128GB of memory, an application, IIS, and many Windows services, is using 107GB, measured with Windows Task Manager. Be sure to set SQL Server Memory Option appropriately (don't leave it at the 2TB default).

  • alan.spillert (6/29/2015)


    Be sure to set SQL Server Memory Option appropriately (don't leave it at the 2TB default).

    Sql server 2012 std will not use more than 64gb ram, it is a feature limitation inside the software regardless of the memory defaults

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    "Ya can't make an omelette without breaking just a few eggs" 😉

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