we recently bought a FAS3140mc storage and I wonder if it exists an efficient way to compute the size of a flexvol (we use the FAS3140mc in pure SAN mode, no CIFS/NFS access).
I do not use snapshots but I've understood that I must keep space for fractional reserve so I can't create a volume which have the same size that the LUNs it contains.
So, do you know a math formula which can help to size my volume ?
For example, if i create a Flexvol with 10 LUNs of 1 TB, should I create a volume of 10.5, 11 TB or any other size ?
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If you're not using snapshots on the volume, it needs to be just big enough to store the LUNs. You do know that you can resize (grow or shrink) a flexible volume after it's created, don't you?
fractional reserve only applies if you intend to use snapshots. if not, forget it.
The other comment is also true, you only need a volume a little bigger than the LUN. For example 1GB.