SQLIO interpretation

  • I have a shared EMC VNX 5300 SAN on which a SQL Server DW is to be deployed. The SAN already supports Exchange, JD Edwards and other applications.

    Even though it is a shared SAN there are 32* 300GB 15K SAS disks dedicated for the data warehouse.

    We have carved 16 LUNs and I am running some SQLIO tests on these 16 LUNs for benchmarking before the DW is deployed.

    Case1: Listing 16 Files (1 per LUN) in a single param.txt file of SQLIO, so that all the LUNs are tested and running 1 instance of SQLIO (Serial)

    Case2: Creating 16 param.txt files having one file listed in each and running 16 instances of SQLIO’s in parallel. (Parallel)

    Questions:

    1. Why do we need to run two tests (case 1 and case 2). How are they different in terms of results (MB/sec)? In which case can we expect more throughput?

    2. To find out SAN wide throughput (for SQL DW), is it required to run SQLIO on all the LUN’s and get a cumulative MB/sec or just running it on 1 LUN will suffice?

    3. The results of SQLIO are across the entire SAN or specific to a disk group or LUN? Is there a way to get the SQLIO results (MB/sec) for a single disk, single LUN, or single DG?

    Any inputs appreciated.

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    I am just an another naive wannabe DBA trying to learn SQL Server

  • There's a lot of good information regarding SQLIO, check the following Microsoft KB link for more info

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

  • EMC should be able to provide you with some information as well. Theoretical IOPs per second and MB (or GB) per second throughput for the entire SAN for starters.

    Also, they should have best practices white papers available for your SAN and/or LUN configurations and HBA settings based upon your performance requirements. What I am saying is that you have a lot of homework to do first before even thinking of using SQLIO otherwise you may be 'spinning' your wheels.

    RegardsRudy KomacsarSenior Database Administrator"Ave Caesar! - Morituri te salutamus."

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