SAN presented LUN size vs. usable LUN size dont match.

[msuvanto_MNIT]

I am looking for a resource for a list or calculator to determine the correct sizes for presented LUNs vs what ESXi sees.

Example:

I am mapping a 8TB FC LUN to my ESXi host.

However the host identifies it as a 7.28TB LUN.

Is the "loss" due to RAW vs. Formatted? - I was under the impression that formatting happens after I add the storage to my host.

Is the "loss" dependent on manufacturer of SAN?

And finally are the any calculators out there or perhaps a simple cheat sheet when it comes to sizing?

Thank you.

[a_p_]

Marketing made a good job in this case!

Storage, and disk vendors usually use marketing sizes (Base 10), whereas ESXi shows the real technical size in GiB (Base 2).

So marketing 8TB equals ~7,2759...TB in real technical size (divide the 8TB four times by 1.024).

Some storage arrays allow to set the size representation to Base 2, so that you can see (and configure) the correct sizes without the need for a calculator.

André