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Using SQLIO block size parameter

  • May 2, 2014 at 1:06 pm

    #307444

    Hello,

    If SQL server writes mostly in 64k blocks why would one want to test with any parameter other than -b64?

    Thanks

    Scott

  • May 2, 2014 at 2:13 pm

    #1710456

    I should know better by now than to post a question on a friday afternoon...:-)

  • May 2, 2014 at 11:10 pm

    #1710488

    Depending on the action (backups, transaction log writes, etc.), SQL Server has several different types of IO sizes, so it is worth testing different block sizes.

    I test with block sizes of 8K, 16K, 32K, 64K, 128K, and 256K for sequential read, sequential write, random read, and random write.

    Depending on the disk size, I use a test file size of at least 50GB to make sure I am overcoming the impact of disk controller or SAN caching.

    I am usually most interested in the 64K random read and random write performance, because many IO systems struggle to get good performance with these. I set up a new server recently, and saw a huge 64K random read and random write performance improvement when I reformatted a volume from the default 4K cluster size to 64K.

  • May 3, 2014 at 5:32 pm

    #1710549

    Ok, thanks much.

    Scott

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