I modified some programs of mine that generate a lot of files to read the old version of the file first, compare it with the new version in the buffer, and only write out the new file if it is actually different. This cuts way down on the write cycles to the SSD. It's faster, too!
An SSD Endurance Experiment: They're All Dead (2015)
21–30 of 54 posts
Re: An SSD Endurance Experiment: They're All Dead (2015)
#22> " Intel doesn't have confidence in the drive at that point, so the 335 Series is designed to shift into read-only mode and then to brick itself when the power is cycled. " I don't understand why Intel wouldn't just configure these drives to go into read-only mode permanently. If I realized my hard drive had become read-only and didn't suspect hard drive failure, my first inclination would be to reboot my computer,…
The article is wrong on this point, and on Intel's intentions, as far as I can tell. Intel has a "Supernova" feature (http://itpeernetwork.intel.com/data-integrity-in-solid-state...) which will cause some drive models to brick themselves if certain conditions are met - errors in the control path, for example, which basically mean you cannot trust the drive at all. The supernova feature is only claimed for enterprise drives, and the 335 series is not an enterprise drive.
I have a lot of experience with long-running Intel SSDs of various models, including pushing them to the same kinds of extreme that the SSD endurance experiment did, and I have never observed them to self-brick simply because they reached their flash endurance point.
What I have observed is a number of firmware bugs (or possibly just the supernova feature) that caused the drive to brick on power cycle, even for drives in perfect health.
I liked the SSD endurance articles, because they went a long way to allaying fears about SSDs, but I think it's a shame they've left this point in.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#23> " Intel doesn't have confidence in the drive at that point, so the 335 Series is designed to shift into read-only mode and then to brick itself when the power is cycled. " I don't understand why Intel wouldn't just configure these drives to go into read-only mode permanently. If I realized my hard drive had become read-only and didn't suspect hard drive failure, my first inclination would be to reboot my computer,…
I don't know Intel's reasoning for this policy, but if there's a sound technical reason for it, I would guess that it has to do with the drive not wanting to flush its NAND mapping information from DRAM to flash that it has deemed worn out. However, the Intel 335 Series uses SandForce controllers that don't have an external DRAM buffer, so they never have much data cached or in flight. It's more likely this policy was decided upon for enterprise products and was deemed not worth revising for client products given how few customers would exhaust the drive's write endurance to be affected by this.
EDIT: And, as pointed out by cuchulain, much of the information about the intended end-of-life behavior of Intel's SSDs is unreliable; they don't publish that information on a per-model basis, so some of what you read is based on mere speculation.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#24> " Intel doesn't have confidence in the drive at that point, so the 335 Series is designed to shift into read-only mode and then to brick itself when the power is cycled. " I don't understand why Intel wouldn't just configure these drives to go into read-only mode permanently. If I realized my hard drive had become read-only and didn't suspect hard drive failure, my first inclination would be to reboot my computer,…
Thanks for reminding me of the EXACT reason that Intel drives were on my personal blacklist of manufacturers to NEVER buy SSDs from.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#25Why do the SSDs all brick themselves when this happens? It seems like a huge mis-feature; HDDs are almost never recoverable when they fail but if you can't reallocate blocks on flash just go into read-only mode.
In principle, going into read-only mode should work and it should take a while for read disturb errors to corrupt the data. But there's a trade-off that if you're trying to keep servicing writes as long as possible (and retiring bad blocks as they wear out), the risk rises that an earlier-than-expected unrecoverable error will corrupt the critical data structures that keep track of the mapping between logical and physical addresses. Playing it safe means quitting early and thus giving your drive an endurance rating that suggests it is less reliable than the competition.
And it's no surprise that the aspects of SSD firmware that by nature get the least real-world testing and are the most tricky to design would be quite buggy in practice. Even ZFS doesn't try to avoid catastrophic data loss in the face of unreliable RAM.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#26It's a fun article but it would have been outrageously good if say 30 examples of each SSD sourced "randomly" had been tested. OK a bit expensive. "Over the past 18 months, we've watched modern SSDs easily write far more data than most consumers will ever need." They tested six SSDs and got "...far more data than most consumers..." - that's the takeaway.
Would you be willing to pay for a subscription to a quarterly report for that info?
For me?
Kind of yes.
Only I have subscription overload. Every newspaper and their dog wants to sell me subscriptions but I generally don't read newspapers daily.
I'd love to have access to this data through some spotify-for-text service or Blendle or something though.
I guess I'm not alone in wanting both to pay researchers, bloggers, journalists etc etc, but based on what I read, not based on a monthly subscribtion to every company that I ever want to read something from?
Re: An SSD Endurance Experiment: They're All Dead (2015)
#27Just wondering how it is compare to HDD: (Here's my calculation base on some assumptions, feel free to correct it if you see any errors.) 2.5PB = 2500TB = 2,500,000 GB 2,500,000 GB / (80MB /s typical HDD Speed ) = 31,250,000 seconds = 8680 Hours = 361 days. It will take HDD 361 days to write 2.5PB at 80MB/s. I wonder how many HDD can survive 361 days of 80MB/s non stop?
Drive vendors are now publishing per-year write workloads for drives.
EG, datacentre-grade SATA and near-line SAS drives like the WD RE (https://www.wdc.com/en-um/products/business-internal-storage...) and Seagate Enterprise Capacity (http://www.seagate.com/au/en/enterprise-storage/hard-disk-dr...) are rated for 550TB/year.
Lower-end drives (NAS, cold-storage, desktop models) are rated less.
Seagate's overall Enterprise/Datacentre lineup (http://www.seagate.com/au/en/enterprise-storage/hard-disk-dr...) ranges from 180TB/year to 550TB/year, and elsewhere on Seagate's site they indicate that a 550TB/year is "10x more than desktop drives".
These are all just ratings though. The theory is that over a population of drives, you'll see a higher failure rate than predicted if you do higher than the rated workload per year. WDC used to have a whitepaper on it called "Why Specify Workload", but it's no longer on their site.
I have in some cases seen enterprise sata drives pushed to the kinds of workload you're talking about - 2.5PB in a year - and seen in the order of 10% fail over that time, with a drive that normally has a ~0.5% AFR.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#28> " Intel doesn't have confidence in the drive at that point, so the 335 Series is designed to shift into read-only mode and then to brick itself when the power is cycled. " I don't understand why Intel wouldn't just configure these drives to go into read-only mode permanently. If I realized my hard drive had become read-only and didn't suspect hard drive failure, my first inclination would be to reboot my computer,…
The article is wrong on this point, and on Intel's intentions, as far as I can tell. Intel has a "Supernova" feature ( http://itpeernetwork.intel.com/data-integrity-in-solid-state... ) which will cause some drive models to brick themselves if certain conditions are met - errors in the control path, for example, which basically mean you cannot trust the drive at all. The supernova feature is only claimed for enterpris…
> I have a lot of experience with long-running Intel SSDs of various models
Hey, could I get your help selecting an Intel SSD model? Overwhelmed by the number of SKUs.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#29Earlier quoted context omitted.
Or if the exact same intermediate files are being overwritten over and over again, wouldn't a RAMDrive be a good place for them?
There's also something to be said for having a build system that can correctly do incremental rebuilds and caching of outputs, which could massively ease the SSD write load.
The CI absolutists tend to yell "reproducible builds" at this point and argue that things should be built from scratch every time.
Re: An SSD Endurance Experiment: They're All Dead (2015)
#30> " Intel doesn't have confidence in the drive at that point, so the 335 Series is designed to shift into read-only mode and then to brick itself when the power is cycled. " I don't understand why Intel wouldn't just configure these drives to go into read-only mode permanently. If I realized my hard drive had become read-only and didn't suspect hard drive failure, my first inclination would be to reboot my computer,…
It was a lie, Intel drive died due to firmware bugs, tldr its shiet despite Intel brand.