Database on different disks

  • Hi all.

    There is heavily loaded OLTP system under Sql Server 2008 Standart Edition. Database has some big tables. My question is about hard disk configuration. Database has problems with I/O (Latches). I have addition RAID and a think about dividing database. There are different options in my mind:

    - Move big tables on additional RAID

    - Move indexes

    Help me, what is better.

    I already moved TempDb on separate disk

  • suvorav (11/5/2009)


    Hi all.

    There is heavily loaded OLTP system under Sql Server 2008 Standart Edition. Database has some big tables. My question is about hard disk configuration. Database has problems with I/O (Latches). I have addition RAID and a think about dividing database. There are different options in my mind:

    - Move big tables on additional RAID

    - Move indexes

    Help me, what is better.

    I already moved TempDb on separate disk

    How big are the tables and what sort of raid do you have?

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  • Thanks for reply

    It is additional RAID 10

    Most large tables are about

    15 millions rows (Data space 2 594,500 MB , Index space 709,766 MB)

    5 millions rows (Data space 1 163,180 MB, Index space 121,539 MB)

    System workload mainly on reading

    I tried to perform load testing with database profiler

    At first I recorded the users workload on production server. After that I replayed one on test server with different database configurations. The replay time was measured, but it was the same time for different variants. Splitting my database does not affect the test execution time.

    Is my testing correct?

    Can you advice any variants of load testing for me?

  • my guess is you have 594.500 MB not 594,500 MB....if so these tables are probably not big enough to see much of a diff...

    you said you moved the tempdb to its own spinal or raid, what about the OS and Transaction logs, are they a diff raids

    then your DB?

    another thing you said you getting mostly reads on these tables? so that tells me you are getting shared locks...which not be a problem.

    have you measured your read/write performance of perf mon...if so can you please post the numbers

  • What are the results of the following queries?

    DECLARE @db_id TINYINT

    SELECT @db_id = DB_ID('northwind')

    SELECT page_latch_wait_count, page_latch_wait_in_ms, page_io_latch_wait_count, page_io_latch_wait_in_ms

    5.

    FROM sys.dm_db_index_operational_stats (@db_id, null, NULL, NULL)

    SELECT * FROM sys.dm_os_latch_stats

    How is your tempdb setup for this database?

    Jason...AKA CirqueDeSQLeil
    _______________________________________________
    I have given a name to my pain...MCM SQL Server, MVP
    SQL RNNR
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    Learn Extended Events

  • The of TempDb is 7000 Mb

    SELECT * FROM sys.dm_os_latch_stats where waiting_requests_count <> 0

    latch_classwaiting_requests_countwait_time_msmax_wait_time_ms

    ACCESS_METHODS_DATASET_PARENT250908472717032106

    ACCESS_METHODS_HOBT_COUNT13618916

    BUFFER278705183513078871529

    BUFFER_POOL_GROW400

    LOG_MANAGER21157601420

    TRACE_CONTROLLER300

    NESTING_TRANSACTION_READONLY16789680216

    NESTING_TRANSACTION_FULL445171122431

    ACCESS_METHODS_ACCESSOR_CACHE1700

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