Its not a shabby san as i say, at the introductory level, but if you struggle for performance it is a controller upgrade to go for, the main problem...
But the biggest different is that a nimble storage array will not slow down when its full - whereas a ZFS array will as its WAFL when the array gets...
Then talk to Nimble - they will save you a shed load of space/cost as there snapshots are soooo much more efficient than the likes of IBM/Dell/EMC.
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