SQL Server Performance

Slow Disk I/O

Discussion in 'SQL Server 2005 Performance Tuning for Hardware' started by DavidDay22, Jul 27, 2007.

  1. DavidDay22 New Member

    I have a Dell 2850 with 8 gigabytes of ram and duel 2.80 Ghz, running under Server 64 bit Enterprize, with SQL 2005 64 bit.

    My disk I/O seems slow, I have 6 15K 146 gigabytes disks in raid 10 connected to a PERC 4e/Di as C drive, and the data and logs split between to arrays of 6 15K 146 gigabyte disks in raid 10 connect to a PERC 4/DC.

    Here are my numbers:
    In memory read test
    spidCallsmsCPUmsCallsPerSecRowsPerCallRowsPerSec
    60254145300009328471.5 10 84715
    6093704300009353123.46730 93704.01
    6035069300009371168.967100 116896.7
    60352730000938117.56671000 117566.7

    Random I/O
    spidCallsmsCPUmsCallsPerSecRowsPerCallRowsPerSecReadsPerSecRead MB/secAvg-sec/IO
    613093001678110.294510102.9451200.32651.56514.9687
    61194300169036.463220129.2644202.35871.58094.9254
    616463001390421.524030645.7202751.67435.872511.9531
    615533000086518.433350921.6667946.63347.395611.9289
    61338300763111.23821001123.82001121.99108.765611.8584
    6112830016244.26443001279.31801263.26009.869212.1472
    614130406231.348410001348.41801286.851010.078712.1770
    611931326360.606530001819.54301750.750013.71149.7875
    61735250480.198699981985.50401880.340014.72659.3380

    spidCallsmsCPUmsdpages/sMBTable MB/secReadsPerSecDisk MB/secAvg-sec/IO
    57128428678714753.8232768115.2642234.7178115.46498.2660
    57126022086816118.3032768125.9242256.1909126.143415.1261

    DavidDay22, Jul 27, 2007
    #2

  2. satya Moderator

    If you have tempdb on those drives which are observing slow I/O, thenrefer to this blog and see this too to check whether you have enabled the online indexing in thsi case.
    satya, Jul 30, 2007
    #3

  3. DavidDay22 New Member

    The read performance for an array of 6 15K drives connect directly connected to a PERC 4/DC controller seems very low, it is almost like somewhere it is throttled
    DavidDay22, Jul 30, 2007
    #4

  4. satya Moderator

    Have you collected the SYSMON counters for further assessment, why not get checkout the hardware with the vendor.
    satya, Jul 30, 2007
    #5

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