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Intel DC S3700 SSD Features New Proprietary Controller
crookedvulture writes "For the first time in more than four years, Intel is rolling out a new SSD controller. The chip is featured in the DC S3700 solid-state drive, an enterprise-oriented offering that's 40% cheaper than the previous generation. The S3700 has 6Gbps SATA connectivity, end-to-end data protection, LBA tag validation, 256-bit AES encryption, and ECC throughout. It also includes onboard capacitors to prevent against data loss due to power failure; if problems with those capacitors are detected by the drive's self-check mechanism, it can disable the write cache. Intel's own high-endurance MLC NAND can be found in the drive, which is rated for 10 full disk writes per day for five years. Prices start at $235 for the 100GB model, and capacities are available up to 800GB. In addition to 2.5" models, there are also a couple of 1.8" ones for blade servers. The DC S3700 is sampling now, with mass production scheduled for the first quarter of 2013."
This is about right. MLC flash normally is rated for between 1k and 10k cycles. Newer flash is generally less as transistor sizes are shrunk to fit in more gbytes in the same die area.
A home PC will only write a couple of gigs a day under typical workloads, which turns out to about 5 full writes a year for even the small sizes. That would last you 4000 years assuming ideal wear leveling...
Basically, what they're saying is this will be absolutely fine for everything except outgoing mail servers and a few other specialist things.
The capacitor backup and write cache make wear leveling much much easier, since all frequently written to cells can be cached in ram, and only written once on shutdown, and the capacitor backup means even an unclean shutdown will save your data.
What are context and indirection tables?
There are some details in this Anandtech article about the tables and the controller's use of DRAM.
What is "proprietary" supposed to tell me about hardware?
There is just so much wrong with calling things "proprietary" and thinking it'll make the reader perceive the product as superior.
TFS does a terrible job of, um, summarizing the situation; but it does actually make sense in context:
Intel's initial entry into SSDs(X-25) was based on an in-house controller, which(with the exception of the unpleasant 8MB firmware bug) was generally quite well regarded. Then it stagnated. They did a few tepid bumps and firmware updates; but no successor controller appeared. With SSDs actually able to saturate a 3GB/s SATA bus, the fact that Intel had nothing on the table for 6GB/s SATA began to become an issue.
More recently, Intel began shipping 3rd party controllers (most recently Sandforce, possibly some Marvel at some point) on everything but their enterprise gear.
Now, after the thick end of four years, they've brought out their first new SSD controller architecture. Whether it does, in fact, turn out to be better is not known; but it is news after such a long hiatus.
Here's the short version - for full details, look at the Anandtech article an above user posted.
An SSD presents itself to the system as just a flat storage device, but internally it does a lot of weird mapping to do stuff like wear-leveling. The indirection table is basically "when the CPU asks for page X, we give them flash cell Y". It used to be a rather clever B-tree, but they ditched that for a flat array to get more consistent latencies.
I'm not sure what the context table is.
The small amount of RAM on Intel's SSDs are not used to cache writes in a significant quantity. The idea that you'll only have to write the most popular cells once per shutdown is a dream. The main benefit of having a bit of reliable capacitor backup is that the drive can be less aggressive about forcing an erase of a large cell just to write a fraction of it out, therefore improving the write amplification situation on the drive. You can even see limiting small writes as a factor in the claimed longevity of the drives if you dig into their spec sheets enough. I did an article comparing the 320 vs 710 series lifetimes, approaching from the perspective of one of those specialist things you allude to--database server operation. One of the things that I noticed there is that the longer lifetime of the 710 came with the restriction that you couldn't do nearly as many small random writes per second (write IOPS) and still hit the claimed lifespan target. If the cache was larger and really effective at postponing writes, that trade-off wouldn't exist.
Except the "dirty little secret" of the industry is its NOT the cells dying that gets you, the controller dying is what bites you in the ass. if it was just the cells since when a cell fails it just ends up read only that wouldn't be so bad, but when the controller fails you flip the switch and...nothing. Not even the BIOS/UEFI detects the thing, its just gone.
That is why even though this article is a year old I'd urge those thinking of diving into SSD to read it, especially the comments where you see guy after guy getting bit in the ass by dead controllers. brand make a difference, OCZ being worst and Intel best, but ALL have this problem to a degree, and when it happens to you? Well lets just hope you have a VERY recent backup.
This is why I tell my customers there are some places SSDs make sense but NOT all. If its mobile, not mission critical, and you religiously stick to a backup schedule? No problem there, if its just an OS drive with the data on HDD? No problem there, just make sure you have recent disc images so you can just clone onto the replacement, but in anything mission critical, or for those that won't stick to a rigid backup schedule? then SSD is NOT the way to go, it'll bite them on the ass and leave them in a bad way.
They really need to come up with a second controller, one that will simply take over in the case of failure and leave the drive in a read only state. this would at least insure that when the main controller does fail you can get the data off, and its those failure rates that are keeping a lot of people (myself included) from switching.
ACs don't waste your time replying, your posts are never seen by me.
Except the "dirty little secret" of the industry is its NOT the cells dying that gets you, the controller dying is what bites you in the ass. if it was just the cells since when a cell fails it just ends up read only that wouldn't be so bad, but when the controller fails you flip the switch and...nothing. Not even the BIOS/UEFI detects the thing, its just gone.
You forget that in a file system you typically write to more than one cell to store some data, what happens when some writes succeed and others fail? Major file system corruption and fast. I've managed to wear out one of the original OCZ Vertex drives - don't know how, I wrote maybe 5 TB to it and ideally it should take 1200 TB @ 10k writes/cell but SMART data was pretty clear. I had a broken file system and each run of fsck made everything worse, I had to stop trying to fix it, mount the thing read-only and salvage what I could. Even that failure mode is not graceful.
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