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  • 1.  format LUN to IBM i

    Posted 08/23/23 02:26 PM

    I have a question, when I create a LUN in storage, for example 200 GB or 256 GB, to add it to an IBM i partition, formatting that LUN gives me less, 185 GB for example, but this margin that it takes away is not the same always, how can I know exactly how much it will take from me? And how much should I create the luns so that when I format them I already generate a 200 GB disk? Sorry, I still don't fully understand some things. greetings



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    Miguel Peralta
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  • 2.  RE: format LUN to IBM i

    Posted 08/24/23 10:19 AM

    The difference in size is caused by the fact that IBM i uses 520 or 4160 byte sectors so there is a translation.  Good explanation on page 532 of this redbook: https://www.redbooks.ibm.com/redbooks/pdfs/sg248503.pdf

    The closest calculation I know of is 9/8 * IBM i capacity = LUN Size.   You may also be seeing the difference between Gigabytes (normally used on IBM i)  and Gibabytes (normally used on Spectrum Virtualize storage) - you can find a calculator for that by Googling it.

    It won't be exact, but do you really need it to be?



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    Vincent Greene
    IT Consultant
    Technology Expert labs
    IBM
    Vincent.Greene@ibm.com


    The postings on this site are my own and don't necessarily represent IBM's positions, strategies or opinions.
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