Intel DC S3700 SSD Features New Proprietary Controller 54
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."
Marketing Speech? 10 writes per day for five years (Score:2)
The article makes me a bit suspicious:
"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."
sounds pretty bad actually, if I understand it right.
Per cell this means: 365*10*5 = roughly 20.000 write cycles per cell? Sure wear leveling algorithms are there, but 20.000 cycles is not exceptional, or am I wrong?
Don't misunderstand this post. I think Intel's SSDs are good.
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20k was good 10 years ago. That number has only gone down... This is due to feature size getting smaller...
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MLC write endurance is usually between 1,000 and 10,000 cycles.
Re:Marketing Speech? 10 writes per day for five ye (Score:5, Interesting)
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.
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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
...unless the disk is nearly full, in which case it'll be writing the same cells over and over again.
(unless the supply a utility which moves data from least-used cells to most-used...)
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...unless the disk is nearly full, in which case it'll be writing the same cells over and over again.
(unless the supply a utility which moves data from least-used cells to most-used...)
That happens even if the disk is nowhere near full, and performing wear leveling is a major part of what the SSD controller does. If you're on a system that doesn't support TRIM, a nearly-full disk could end up with write amplification problems, though.
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(unless the supply a utility which moves data from least-used cells to most-used...)
All SSDs do wear levelling, otherwise they'd die after a couple of days. That happens beneath the LBA address layer - i.e. LBA's are mapped to physical addresses and the mapping changes each time an LBA is written.
So you don't need to do wear levelling at the file system level. In fact the only thing you need to do there is to have a TRIM command which tells the SSD that a range of LBAs no longer contain useful data. That means the SSD can mark them as obsolete which gives the wear levelling a bit more elbo
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(unless the supply a utility which moves data from least-used cells to most-used...)
All SSDs do wear levelling, otherwise they'd die after a couple of days. That happens beneath the LBA address layer - i.e. LBA's are mapped to physical addresses and the mapping changes each time an LBA is written.
Point is: Wear levelers are only useful of they've got some free space to work with. If they haven't got any (ie. disk nearly full), ...then what?
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You've always got a free erase unit, because at least one is reserved for wear levelling. It's easy to invent an algorithm that moves that free unit around the the disk by garbage collecting from a full unit to an empty one.
There are papers on this sort of thing. Look at the patents M Systems filed for example, or the documentation on TrueFFS. I've worked with embedded systems that used that and one of the first things we did after we got a socket driver working was to hammer a full disk and check that
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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.
Data retention figures would be interesting too. Last I heard, the strategy for dealing with that at smaller feature sizes was to make the disk periodically rewrite all the data, which of course will eat into your write cycles.
[checks articles] ....ugh. Is that seriously it?Three months? [hothardware.com]
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This isn't unprecedented. When I looked into the 710 series models [2ndquadrant.com] it was the same trade-off: those drives were also only specified to save their data for 3 months between refreshes.
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[checks articles] ....ugh. Is that seriously it?Three months?
Wear retention on flash is kind of a bummer for time capsules and Stargate style ancient repositories of knowledge. An old school PC with a bios in mask rom should be able to boot up given power in hundreds of years time, assuming the hard disks don't have some sort of failure mode that happens when they are un-powered.
A modern machine has firmware in flash and also a flash drive. Both of which would end up blank in a few years to a few decades depending on technology with more recent being worse.
If I were
Re:Marketing Speech? 10 writes per day for five ye (Score:4, Informative)
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 [wikipedia.org] 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 [2ndquadrant.com], 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.
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Re:Marketing Speech? 10 writes per day for five ye (Score:4, Interesting)
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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So basically, you got "lucky" and some of the cells failed. From what I've heard it's more often the controller that gives up causing the disk to change overnight from a nice piece of electronics into a shiny paper-weight. No hope for recovery at all; the thing simply won't show up in the BIOS. Because of this it's also impossible to read the SMART info so it's hard to say if the controller failures are related to some cells being end-of-life confusing the hell out of the controller or if it's something els
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Not quite correct either.
It's not the controller hardware dying, it's the controller firmware crashing and burning.
A few days ago, my Crucial C300, a drive I've been running like mad for 2 years, finally critically failed to read back a sector. And instead of returning an disk error, the entire drive froze. After waiting 15 minutes to see if it'd come back, it didn't. Rebooting, then rereading resulted in the same drive crash. Overwriting the sector with dd made it force a remap and allowed me to fully imag
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Assuming 6Gbps and assuming you never stop writing, you crash the disk in one month. It is indeed pretty low. Most SSDs would last a couple years at full write speed.
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Here what they are saying is clear. As someone considering the drive I can easily say (without doing any sums) that my use case is nowhere near as "bad" as the pathologically SSD unfriendly situation they describe and quickly conclude (to the extent I trust their information) th
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The article makes me a bit suspicious: "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." sounds pretty bad actually, if I understand it right. Per cell this means: 365*10*5 = roughly 20.000 write cycles per cell? Sure wear leveling algorithms are there, but 20.000 cycles is not exceptional, or am I wrong?
With an Intel SSD you never actually get anywhere near the total number of write cycles. Because of a special Intel wear-levelling feature called BAD_CTX 0000013x the drive will brick itself periodically [intel.com], forcing you to erase it and resetting the write config. It's a clever feature of Intel SSD products that I haven't seen other manufacturers implement yet.
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It's like the Colonel's 11 secret herbs and spices. If you trust the brand, it's a plus - if you think that KFC is including human remains as a "spice", it's a negative. In this case, it lets you know that there is something unique about this new Intel SSD that no other brand has. Whether that is good or bad depends purely on your feeling about Intel's level of competence in designing SSD controllers.
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"Original recipe is people!" This reminds me of the urban legend [snopes.com] that fast-food burgers were made with worms that I remember hearing back in the late 70's.
Re:Proprietary (Score:5, Insightful)
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.
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Point is, they're behind the competition. There are faster (and cheaper) drives out there now.
So, this may work in the long term - but they're just another competitor in the mix at the moment.
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there are NOT faster and cheaper drives in the market with these features, there's nothing out there right now, to my knowledge, with is capacitor-backed cache and end-to-end integrity.
for the price intel is asking, its quite reasonable as well.
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samsung 840.
done in one.
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Intel was shipping their own controllers for the low end, and using Marvell's for the high end with the 510.
Then Sandforce for the 520.
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What "proprietary" means to me here is "untested and likely to be very buggy". I've helped people cope with losing terabytes of lost data eaten by Intel's early X-25 models, when they first played this game. The “BAD_CTX 13x Error” AKA 8MB size bug sucked; so did their flat out deception about the drive's write cache [mysqlperformanceblog.com] in order to cook benchmark results.
At least they're honest about which drives do and don't care about cache integrity now, and firmware reliability of the models that do that righ
What's stored in DRAM? (Score:3)
The article says this:
The controller has a 6Gbps Serial ATA interface, and a gig of DRAM rides shotgun.This DRAM cache never stores user data but is instead used for context and indirection tables.
That detail is important in light of the DC S3700's power-loss protection, which uses multiple onboard capacitors to ensure that in-flight data is safely written to the flash in the event of a power failure.
What are context and indirection tables?
Re:What's stored in DRAM? (Score:4, Informative)
What are context and indirection tables?
There are some details in this Anandtech article [anandtech.com] about the tables and the controller's use of DRAM.
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Re:What's stored in DRAM? (Score:4, Informative)
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 end of on-site backup? (Score:2)
With this drive I would feel ok ditching my onsite weekly backup and only having a single off-site backup.
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At the beginning of its release cycle, the odds of firmware bugs eating all your data is massively higher on this drive than the models that re-used existing controllers/firmware and have been out a while. The new controller means they've basically started over again with a firmware rewrite. PC hardware and software has so many possible configurations to test, it's impossible to get that right without beta testing the hardware in the field to see what problems the sucker early adopters get nailed by. The
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That is a concern, but AES encryption is not for yet another descendant of CPRM... it is because a lot of companies and government organizations require DAR (data at rest) encryption. Having this done at the HDD controller level is the best for performance reasons, and with the latest version of BitLocker, drives are recoverable (recovery info is stored in an AD schema), but still secure if someone decides to "borrow" a few drives out of a drawer.
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That makes sense -- it also prolongs the cell life when just the AES key is zapped and only new data forces an erase, as opposed to overwriting every block when a ATA secure erase command is given.
Faster as well.
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But as a nerd, this is news. I'm a big fan of Intel controllers and am looking forward to taking this for a test drive.
Proprietary = back door. (Score:1)
If you want to make sure your data is safe from prying eyes,
choose another drive.
Posted anonymously because doing otherwise would jeopardize my job.