2 Replies Latest reply: Feb 13, 2018 8:39 PM by dynamox RSS

Calculating thin savings

dynamox

Hello guys and gals,

 

I am looking at this numbers and they are not adding up. 

 

            "logical-space-in-use": "56724912",
            "thin-provisioning-ratio": 0.083384457300000006,
            "vol-size": "680281600",
            "thin-provisioning-savings": 91,

 

I have 648.77G worth of volumes created on XIO, host has written 54.09GB worth of data.  Why is it reporting 91% in thin savings ?

 

648.77 - ( 648.77 * 91%) = 58.39G

 

Thank you

  • 1. Re: Calculating thin savings
    scotthoward

    The thin savings is the percentage of space on the array that is thin provisioned.

     

    In your case, you've got 54.09GB of volumes, out of a total of 648.77GB of volumes (it's actually 54.10GB and due to rounding, but I'll use your number for consistency)

     

    That means that the thin provisioned space is (648.77-54.09=)  594.68GB

     

    Thus the thin percentage is 594.68/648.77, which is 91.66%  By the looks of it, the result returned is being rounded down, so you get 91%.  (It should probably be 92%)  Going backwards from that number like you've done is going to give an incorrect result due to the fact the percentage is being rounded - your math works if you use 91.66%, but is off if you use either 91% or 92%.

     

    The thin-provisioning-ratio will give you the same number more accurately - 1-0.08338 = 0.91662, or 91.66%

  • 2. Re: Calculating thin savings
    dynamox

    Thank you Scott, the two missing decimals (91.66) tripped me up.