XinXu

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13 years ago

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XinXu

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July 24th, 2013 00:00

Question about Thin pool considerations

Hi Experts,

I'm reading the technical notes about the Best Practices for Fast, Simple Capacity Allocation with Symmetrix Virtual Provisioning Technical Note. I have some question about the content of Thin pool considerations on page 27:

"Data device sizes should be as large as possible to minimize the number of devices required to encompass the desired overall pool capacity."

"Each drive must be divided into at minimum eight hypers in order to maintain adequate disk queue depth."

I don't fully understand above sentences, can anyone help on this?

  • A-J1

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    Posted July 24th, 2013 06:00

    this basically means that if you are creating a pool of suppose 1 TB, you can create

    10*100GB TDAT's

    OR

    20*50GB TDAT's

    OR

    40*25GB TDAT's and so on, BUT we dont want the number of tdat's to be too high, data is striped on tdat's in the pool, we want every spindle to be used atleast once,creating too many TDAT's will cause the same spindle's to be used multiple times which can degrade performance.


  • Quincy561

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    Posted July 24th, 2013 06:00

    We found that 8 splits or hypers per disk was the sweet spot for performance.  There are cases where you will need more to utilize the capacity.  In those cases you should try and keep the count as low as possible.

    Even is good as well.

    And all drives in the pool should have the same number of TDATs, and they should all be roughly the same size, with the exception of drives with internal use storage on them such as vault and SFS.

  • XinXu

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    Posted July 25th, 2013 19:00

    Thanks all for the advices.

  • Fenglin1

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    Posted July 25th, 2013 19:00

    The "each drive" in the sentence means physical drive you create the TDATs. The recommendation is that creating 8 hypers on each drive for you TDAT will having better performance.