Storage Marketing is one of maddest and craziest parts of the technology industry; so many claims that don’t necessarily stand-up to scrutiny and pretty much all of them need to be caveated with the words
‘It Depends….’
And actually it is very important to understand that it really does depend; for example, when your flash vendor claims that they can supply flash at the price of spinning rust; they may well be making assumptions about deduplication or compression and your data.
If you are in a highly virtualised environment, you might well get a huge amount of deduplication from the operating systems..actually, even if you are not and you utilise SAN-boot, it’ll dedupe nicely. But what if you store your operating system on local disk?
What if you are already utilising compression in your database? What if your data is encrypted or pre-compressed media?
Of course this is obvious but I still find myself explaining this at times to irate sales who seem to assume that their marketing is always true…and not ‘It Depends’.
Understand your data…understand your access patterns…decide what you are trying to achieve…understand true costs…
The problem is that many of us don’t have time to carry out proper engineering tests; so I find it best to be as pessimistic as possible…I’d rather be pleasantly surprised than have an horrible shock. This means at times I am quite horrible to vendors but it saves me being really nasty later.