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Power-Loss-Protected SSDs Tested: Only Intel S3500 Passes
lkcl writes "After the reports on SSD reliability and after experiencing a costly 50% failure rate on over 200 remote-deployed OCZ Vertex SSDs, a degree of paranoia set in where I work. I was asked to carry out SSD analysis with some very specific criteria: budget below £100, size greater than 16Gbytes and Power-loss protection mandatory. This was almost an impossible task: after months of searching the shortlist was very short indeed. There was only one drive that survived the torturing: the Intel S3500. After more than 6,500 power-cycles over several days of heavy sustained random writes, not a single byte of data was lost. Crucial M4: failed. Toshiba THNSNH060GCS: failed. Innodisk 3MP SATA Slim: failed. OCZ: failed hard. Only the end-of-lifed Intel 320 and its newer replacement, the S3500, survived unscathed. The conclusion: if you care about data even when power could be unreliable, only buy Intel SSDs."
Relatedly, don't expect SSDs to become cheaper than HDDs any time soon.
There's still one 720RPM laptop drive, I just bought a 1TB 7200RPM HGST drive recently...
That said one of the newer Seagate drives scored faster in a speed check. Not sure what to make of that.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
Or get an m500 which is basically a m4 with capacitor backup and newer NAND.
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HDDs, even the cheapest ones nowadays, allow the software to enforce the order in which pending data is written to safe permanent storage and software to known that pending data has indeed been safely committed to permanent storage.
The operative systems, file systems and applications build upon this to ensure that, in case of an unexpected crash, you don't end up with a corrupted file system or data. You may lose files created in the last 5 minutes, but you won't end up with a file system so corrupted that you need to re-install your computer.
Databases uses this to ensure that, once you've clicked "pay" in a e-commerce site, it will either record it properly or not at all, so you don't end up with half-way situations where you get charged and don't get the product you paid for or vice-versa.
According to reports like TFA and the article TFA was attempting to reproduce, a lot of cheap SSDs break this guarantees.
Technically -yes-, but the issue can be catastrophic with an SSD where as with an HDD, you just loose maybe a file. Both the drive and a journaling filesystem should be able to recover from. With an SSD however, the LBAs are not mapped predominately to memory cells. They get reassigned based on whatever algorithm of wear leaving is employed. If this separate abstracted database to the drive's firmware itself becomes corrupted, you could lose the entire drive. And that's the problem, yet another abstraction that SSDs use that's completely vulnerable to uncommitted writes-backs from power failure. This is something where the OS and filesystem can't help you on an SSD. Unfortunately.
Life is not for the lazy.
The power loss protection on the Crucial M500 worked fine in my initial tests. It can't be taken seriously as a reliable drive because it doesn't have any SMART data on longevity. There's no way to know when the drive is wearing out, so it's pretty much useless for serious work. The one I bought for testing is in my laptop, it's a fine drive there. See Tech Report for a review complaining about the missing SMART data, I'm not the only one who noticed.
Intel's data on wear is very good, see my look at the 320 vs. 710 lifetime for example. The replacement models, DCS3500 and DCS3700, are even better drives in every way.