XIV GUI and the decimal/binary divide

For someone who blogs so frequently about the IBM XIV,  I will let you in on a little pet hate of mine:   The XIV uses decimal volume sizes.

The XIV GUI and CLI  has the user create volumes using decimal sizing, meaning 1 GB = 1,000,000,000 bytes (1000 to the power of three).
Nearly every host system out there (i.e. Windows, AIX, Linux, VMware, Solaris) display volume sizes in binary, meaning 1 GiB = 1,073,741,824 bytes (1024 to the power of three).

This disparity has a quirky consequence.   If the XIV says a volume is 17 GB, the host that uses that volume says it is 16 GiB (which the host often then mis-states as GB).   This doesn’t mean there is a loss of space, this isn’t headroom or formatting – its just a different way of counting bytes.  Its not a road block and its easy to understand and work with.   But it is a little annoying.    (Then again, so is my 32 GB iPhone reporting it has 29.3 GB of space).

The other point is that the IBM SVC, Storwize V7000, DS8000 and DS3000/DS4000/DS5000 families have always used binary sizing (even if their respective interfaces use the term GB as opposed to GiB – yet another pet hate of mine and the Storage Buddhist).

So whats the point of this rant?

The IBM XIV Storage System GUI (Version 3.0) will allow volume creation in both GiB and GB units.  The IBM XIV Storage System management GUI version 3.0 will support the creation of volumes in Gigabyte (GB) or in Gibibyte (GiB) or Blocks (where each block is 512 bytes).

So this is a really good change.

The new GUI has not hit the download site yet… but I will be sure to tell you as soon as it has!

*** Update 08/09/2011 – corrected GUI version from 2.5 to 3.0, removed some confusing terms ***


About Anthony Vandewerdt

I am an IT Professional who lives and works in Melbourne Australia. This blog is totally my own work. It does not represent the views of any corporation. Constructive and useful comments are very very welcome.
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