3 thoughts on “Dynamic Provisioning: v1.3 of Unofficial Best Practice guide available

  1. Peter

    Hi Nigel,
    A couple comments on the white paper. 
    1.  It’s not possible to mix internal and external LDEVs in the same Pool. 
    2.  Where did you find the diagram’s on page 10 and 11?  There is no evidence that I am aware of that supports your discription of how pages are allocated. 
    3.  The Initialize/Optimize comments are misleading.  The user guide states that it will only optimize unallocated pages in the management table. 

  2. Nigel Poulton

    Hi Peter,

    Thanks for reading the doc and giving some feedback.  See my repsonses below –

    Point 1.  I guess you are referring to me saying it is best practice not to do that.  I honestly cant remember, but may be in earlier versions of ucode the GUI let you do it, and only recent versions realised it was such a bad idea and not dont actually allow you to.  Thanks for pointing it out though!

    Point 2.  I created the diagrams myself.  However, the point I am presenting is correct.  I know the algorithm and formula for calculating "striding" and free page organisation including the dimensions and organisation of the Free Page List etc etc.  However, I will not be putting this information in the manual because it is NDA/Hitachi proprietary…  The principle presented in the diagram is correct, despite the fact you cant find them in the manual.

    Point 3.  In the next release I will make it more clear that optimising the pool after new LDEVs are added will only optimise the unallocated pages.  I do not think the current comment is incorrect (I am aware of how it works), I think it is open to interpretation, I will nail it down in the next release.  Unless of course they come along with levelling a’la EVA…..  😉

    Let me know if there is anything else.  Nigel

  3. Pingback: Hitachi Virtual Storage Platform – VSP – Technical Deep Dive

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