Flash is dead ... but where are the tiers?

Perhaps not the place to get into this but,

Given that you can pick up an old school External 2TB HDD with connections for USB3.0 for less then 90.00€.

BTW: Why are External HDDs almost always cheaper then there Internal cousins?

Where is the incentive to get a 250GB SDD for no less then TWICE this amount?

Call me greedy, but I for One demand more BANG [e.g. Available Space] for my Buck.

Why would some Bean-counter see this any differently?

If Flash can be saved. It needs to step up to the Platter Capacities 1TB+ and match damned well on price. A slight premium would and should be expected. But when a given 250GB SATA II Drive costs 'round 40.00€ you're talking about a 225% premium, and we're talking about the difference between filling up a Multi-bay NAS RAID Array or just the One low capacity Drive.

Damn! You got me going!

I thought the title was about Adobe Flash.

No such luck, that's still going to be clinging on for dear life in applications like BBC iPlayer.

Electrical Engineers To The Rescue !

"Committing" a transaction to volatile memory (ie. using DRAM as an tier in the storage hierarchy) of course is quite fishy. Can you really depend on the backup power supply of the DRAM to work with high reliability ? Can you assure the same level of reliability as "written on magnetic material" or "written into flash memory" ?

If you don't do handwaving, you need three redundant DRAM copies which can each burn down without affecting the other. That means full galvanic isolation from external power/ground lines. It's doable, but it will require good engineers and some money.

But of course, DRAM mass storage would allow for very high transaction throughput. For some applications (e.g. OLAP) you don't need transactional guarantees, so you could skip the three-copy redundancy requirement.

Its fascinating watching people make pronouncements about what technology will look like in 10 years. Saying flash *will* be dead in the next 5 to 10 years but that spinning rust will hang around for longer is not really a statement that holds up.

Sure, 2D floating gate NAND flash will be dead in a few years, replaced by charge trap NAND, and/or 3D NAND, but it will still look like flash as far as you can tell. At some point 3D NAND gets replaced but ReRAM or some other technology, but it will still look like flash as far as you can tell. At some point ReRAM or whatnot gets replaced by yet another technology that hasn't even been chosen yet, because its so far in the future, but it will probably still look like flash as far as you can tell.

Now as far as spinning rust goes, sure it will be around but its not going to look like the disk drive you are used to. HDDs are running into their own scaling issues, and once they go to shingled magnetic recording (SMR) they turn into something like a cross between flash and a file system. This is not the disk drive you are used to. If anything is going to be *dead* in the data center its the hard drive, too slow, too unreliable, too much power consumption.

As far as flash pricing goes when buying tier-1 storage you are buying performance not GB, if $/GB was all that mattered no one would buy anything but tape, or maybe slow SATA drives. The reason people buy 15K SAS drives is because they understand they are buying performance not bulk storage. And that is why people flash. Even for what some might call tier-2 storage used for VDI and other apps, people buy flash because disks are just too slow.

Enterprise storage is so much more than $/GB, disk storage could be free, but that doesn't matter if it takes more space than you have, more power than you have, more cooling than you have, can't provide performance for the applications that you have, or more importantly the applications you wish you had if only your storage was fast enough to run them.

As far as tiering goes (no I wasn't going to forget about tiering), while I could dispute the cost differentials of storage *systems* as opposed to just looking at component prices, I will just observe that I think saying it will never happen that applications will manage their data is pretty clearly not going to be the case, toss in app aware/guided file systems and/or hypervisors and I think that would definitely not be a safe prediction.

And I'm sure such tiering systems will come in handy for moving your data between your performance SLC storage, your bulk MLC storage, between your bulk MLC storage and your TLC archive/backup storage. Standard mechanisms will probably suffice to move your data to your long term SATA archive storage.

Don't believe that tiering will wind up being between memory types rather than between memory and disk. That's ok, people scoffed at the idea of disk to disk instead of disk to tape backups too.