Judging cost versus value is perhaps the trickiest balancing act in any purchasing decision, and flash storage is no different, especially when health IT managers put it up against the price of HDD.
For example, grappling with just this issue in a recent column, George Crump, president of Storage Switzerland, pointed out, “the raw price per gigabyte of flash is declining rapidly due to an increase in production and density per flash cell.”
But then he immediately observed that that per gigabyte price drop is often offset by the reality that flash can be less durable than HDD. Then again, he added, “an AFA largely mitigates the impact of faster wear out. Most AFAs have redundant components, so if a NAND wears out there are other NANDs available to take its place. The majority of all-flash array vendors over-provision the drives, so they may only present 75% of the capacity of the drive to the storage system. Over-provisioning allows fewer writes across more NAND cells. While sacrificing some capacity, it does extend the apparent life of the drive.”
All of which is perhaps a long way of making the simple point that, well, the price of flash storage is complicated.
Crump explains the number of ways flash pricing can get a little “fuzzy,” due in large part to what are dubbed “data efficiency” considerations, and then he lays out three potential approaches for IT managers to use. Option one: “take a very conservative approach and buy with the assumption that there will be no gains in capacity from data efficiency.” Option two: assume a 2.5 times data efficiency gain. Option three: push for a data efficiency guarantee that many vendors are now providing.
As Crump’s sees the decision, flash pricing is not exactly a precise science, which, in his view, means IT managers have to understand all the available options then drive for the best bargain.