Who’d have thought that EMC’s storage teenager, the Symmetrix/DMX, still had the ability to surprise us with something new? Well, as reported just about everywhere, EMC today introduced two major new features in the DMX. But don’t get fooled - this is still traditional high-end EMC stuff, and you had better be sitting down when you see the price!
EMC SSD - Old is New Again
Check out The Storage Anarchist’s definitive (for now) take on the flash announcement!
A long time ago in Hopkinton, EMC sold a line of solid state storage systems for high-performance applications. This was way back, before blogs, the world wide web, WiFi, Network Appliance, you get the picture. The Allegro/Orion/Atom was actually introduced even before NAND flash itself, in 1988! That product evolved into the Symmetrix platform we now know, and as of today history has wrapped back on itself with EMC’s introduction of solid state storage for the Symmetrix.
I’ve long hollered that typical consumer flash drives weren’t suitable for the enterprise storage market, and EMC has now confirmed that I was right. Rather than slap a commercial flash drive into a storage array and call it a day, EMC and their supplier , STEC, reinvented the flash drive altogether. Please re-read that, and drill it into your head - the new EMC/STEC SSD is an altogether different animal than other flash-based SSDs!
So what’s wrong with consumer-level flash and what’s right about EMC’s SSD? Typical multi-level cell NAND flash (as used in your thumb drive or iPod) used two tricks to boost sequential performance and density at the expense of longevity and write performance:
- They write large blocks of data at once, which increases sequential performance to an acceptable level but requires large amounts of data to be rewritten when a small amount changes, hurting random write performance and longevity
- They store multiple values in a single cell which boosts density but exacerbates the problems pointed out above
As Tom’s Hardware noted when they tested commercial NAND-based SSD drives, random write performance was downright terrible because these drives just weren’t built for this I/O pattern.
EMC’s new SSD drives are completely different from the drives tested by Tom’s. They use single-level NAND cells, eliminating problem number one and greatly reducing wear. They also include generous on-”disk” RAM caches and optimized array firmware leveraging the array’s own cache to reduce the random write performance hit noted in problem number one. Finally, the SSD drives include extra capacity set aside for when highly-used cells wear out. With these three modifications in place, I bet EMC really will be able to wring out amazing performance and acceptable longevity.
So what’s the catch? Price. Although I don’t yet have any pricing information, I’d be shocked if these new SSD drives aren’t 10 times more expensive than their spinning metallic brethren. Consumer-level flash drives are already expensive on a per-GB basis, with a 64 GB SATA unit going for $1,500 or more, and EMC’s exotic drives will be much more expensive than this. That single-level NAND, for one, will drive cost through the roof, since these chips aren’t mass produced at anywhere near the same volume as regular multi-level NAND. Add in the fact that these are custom drives built just for EMC, and you’re looking at some serious dough.
Since the company is positioning these drives at the highest of the high end, that price probably won’t matter as much. Any application that really needs this kind of storage will (grudgingly) bear whatever the cost. But don’t expect massive volume shipments in the foreseeable future.
One More Thing…
In the best Steve Jobs tradition, EMC also released another major new upgrade for the DMX, “virtual provisioning.” Although it’s likely to be overlooked by those overcome with flash fever, this has much broader appeal for the DMX customer base. Essentially, it’s an EMC-think version of thin provisioning, which allocates actual disk capacity as it is used by applications rather than as it is provisioned by storage administrators.
What sets EMC’s virtual provisioning apart from everyone else’s thin provisioning? Not a lot, actually - except that it’s universally supported across DMX configurations. So you can do whatever you want with it, even replicate thin-to-thin, which is nice. But calling this by a new name just because it (allegedly) works is a little misleading in my book…
You can read more about these announcements at Chuck Hollis’ blog, Storagezilla, and probably everywhere else in short order. I can’t wait to hear what Hu, Toigo, Tony, and the rest have to say! Who’d have thought that the day before Macworld would be this interesting?!
Update:
- TechTarget reports that the flash drives will be 30 times more expensive than conventional disks!
- STEC’s press release for the Zeus-IOPS drives has some more performance numbers. I’m just diving into their product information for the drive.
- Chris Evans, The Storage Architect, noted the addition of 1 TB drives as well.
- Robin Harris suggests that flash disks are more like 75x the performance of a disk drive, rather than the 30x EMC is consistently claiming, and also that Texas Memory Systems’ Ram San offers nearly twice the performance!
- Industry veteran, Fred Moore, chimed in with some history of SSD storage!
- Gear6’s response will be interesting - they’ve got some very cool technology for accelerating storage!
gschulz | 14-Jan-08 at 3:57 pm | Permalink
Steve you are spot on in saying that there are differences in SSD (FLASH vs. RAM) as well as packaging including standalone system (e.g. Solidatata, Imperial-RIP and others) vs. drive form factor (STEC, MTRON, Curtis, Samsung, etc.) vs. PCI card based accessible only to the server attached to them (e.g. FusionIO) vs. caching appliances like Gear6 among others) and even in the components, or consumer flash vs. enterprise flash and so forth.
SSD in generally is on yet another one of its up cycles which we have seen several times over the past several decades, this time however particularly when you combine RAM+FLASH+HDD as part of a solution, we may not see the typical downside cycle of SSD as we have seen in the past. Heck you can even get a FLASH based SSD to install or retrofit your favorite laptop now.
With each up cycle, we see new vendors; new packaging and so forth along the departure or demise of some others, and some even have hung around for a couple iterations. In the past SSD was about RAM storage with first battery backup (BBU) and then BBU + hard disk drive (HHDs) either standalone or mirrored or raid protected for persistency. Likewise SSD historically was perceived as only being for IOPS which in early generations was the case, however some later versions also do very well on bandwidth.
What’s different about this new hybrid generation approach is that they leverage RAM as the cache to front end and mitigate the write downside to flash (wear and tear as well as performance), back to the future? Some of the HDDs manufactures have announced early generations of Hybrid Hard Disk Drives (HHDD) that combine some RAM plus some FLASH plus a regular HDD, we have seen some VARs do some creative packaging of the above combinations for a Hybrid, we have seen vendors like TMS combine RAM as the cache, and FLASH in a RAID5 for persistence and protection mode and now we come full circle to EMC and the DMX and FLASH, again, back to the future?
Here’s what’s interesting is that the Symm/DMX uses RAM as cache (among other techniques and technologies) to boost HDD performance, now they use RAM to front end FLASH in a similar way as they have done in the past with HDDs. This is similar to what TMS is doing with their RAM-SAN500 which leverages the RAM as cache, and the FLASH as persistent storage.
Folks it is back to the future yet moving ahead and welcome to the many faces of SSD that if not already in your future, will be sooner or later. Learn more about SSD and how FLASH based SSD can help achieve energy efficiency in the industry trends and perspective report at http://www.storageio.com/Reports/StorageIO_WP_Dec10_2007.pdf or other related material at http://www.storageio.com/xreports.htm.
Cheers
GS
Stephen | 14-Jan-08 at 4:06 pm | Permalink
Thanks for the thoughtful comment, Greg!
Folks, I highly recommend Greg’s StorageIO analysis. As you can see here, he really knows his stuff!