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Backblaze Drive Stats for Q3 2023

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Re: Backblaze Drive Stats for Q3 2023

#61

Post by Dalewyn »

gruez wrote: post #60
jbverschoor wrote: post #58

Earlier quoted context omitted.

Sure.. until it gets decrypted

Is that a realistic threat with AES-256 and randomly generated keys?

There's a reason that the industry standard for proper disposal of storage media, including HDDs, is nothing short of physical destruction.

It doesn't matter if the data is encrypted or not, the point of the matter is the data is still there when presumably that data should not exist outside premises. Encryption serves as a mitigation against theft or accidental leakage of data, its purpose is not to facilitate data disposal.

Put another way, you have to answer Yes to this question for liability purposes: "Is the data gone?" The only way to say Yes with reasonable certainty is physically destroying the storage medium the data resides on.

Re: Backblaze Drive Stats for Q3 2023

#62

Post by gymbeaux »

gruez wrote: post #60
jbverschoor wrote: post #58

Earlier quoted context omitted.

Sure.. until it gets decrypted

Is that a realistic threat with AES-256 and randomly generated keys?

The local electronics recycling company where I live (US-FL) shreds hard drives by default and many of their enterprise clients apparently ask for it when they “donate” their old PowerEdge servers, NASes and whatnot. Now obviously the recycling company could try to discourage this in lieu of a 3 (or 7 or 100 or whatever) zero of the drives and then resell them as they do everything else they get “donated” to them… many are really expensive, high-capacity SAS drives that are only a few years old. But I guess nobody wants to be that guy who compromises company data or whatever just so the local recycling company can make money off their old drives in addition to their old servers, UPSes, racks, et al.

Of course if these companies were really smart, they’d have wiped the drives before going to the recycling company. I’m sure many do. Still, they don’t risk it and want the drives shredded.

Eventually, AES-256 can probably be bruteforced in a reasonable amount of time. If you write all 1s and then all 0s (or vice-versa) to the drive, on the other hand… there’s no way to recover the data. There’s a lot of debate about that statement, but ultimately, if the drive is in fact zeroed twice, it’s physically impossible to recover the data. The debate seems to be mostly around whether zeroing a drive really does zero every bit and that’s not straightforward to prove (many drive erasure programs will offer a printable “certificate” once a drive has been “secure-wiped”, which often mentions a “million dollar guarantee” or whatever… it’s a sham because how do you prove the program failed to erase the data on the drive? Especially days, weeks, or years later?).

Re: Backblaze Drive Stats for Q3 2023

#63

Post by gymbeaux »

Dalewyn wrote: post #61
gruez wrote: post #60

Earlier quoted context omitted.

Is that a realistic threat with AES-256 and randomly generated keys?

There's a reason that the industry standard for proper disposal of storage media, including HDDs, is nothing short of physical destruction. It doesn't matter if the data is encrypted or not, the point of the matter is the data is still there when presumably that data should not exist outside premises. Encryption serves as a mitigation against theft or accidental leakage of data, its purpose is not to facilitate data…

Well, if you write 1 to every bit of the drive, and then write 0 to every bit of the drive, the data is gone… but to be fair, I think the concern is proving that actually occurred before disposal. It’s easy to see the data destroyed when the drive is ground up before your eyes.

Re: Backblaze Drive Stats for Q3 2023

#64

Post by gymbeaux »

dehrmann wrote: post #15

> The average age of the retired drives was just over eight years Didn't realize they can last so long.

I have a 3TB Seagate from around 2009 that still works. It was shucked from an external USB enclosure and has moved desktops several times. Granted its use has been pretty intermittent. Right now it’s just sitting on my desk, as it often has.

I have some ~140GB SAS drives HP branded that are probably of similar age based on the capacity, and they still work… but again, they haven’t exactly been active for the last 15 years straight.

Re: Backblaze Drive Stats for Q3 2023

#65

Post by kqr »

andy4blaze wrote: post #32
kqr wrote: post #13

Earlier quoted context omitted.

I have always wondered why they don't use techniques from survival analysis to be able to draw conclusions even from sets with lower failure rates. Or for that matter to avoid slight bias even for drives they do report.

Andy Klein from Backblaze here. We have done some survival analysis (kaplan-meier curves). In our case, we need to have a reasonable number of failures over the observation period to get decent results. You can take a look at some of our work here: https://www.backblaze.com/blog/hard-drive-life-expectancy/ and see if that is what you were expecting.

Yes! Thank you. I've been thinking about scratching this itch myself but it turns out you did already.

In particular the shape of the survival curve interests me -- you hear so many things about exponential here, bathtub there, but ver little data. I will read once I have a spare moment.

Re: Backblaze Drive Stats for Q3 2023

#66

Post by defrost »

andy4blaze wrote: post #6
nicolaslem wrote: post #3

The article discusses the impact of high absolute temperature on the longevity of drives, however from my amateur knowledge the range of temperature during a day is also an important factor. I always assumed that having a stable 40°C is better than a drive constantly swinging between 20°C and 40°C, so I am surprised that the article only mentions alerts on reaching a high threshold.

Andy Klein from Backblaze here. Your point is a good one in that temperature fluctuation can be an important factor. We actually sample smart stats, which contain the temperature attribute, multiple times a day looking for such changes. The Drives Stats data is captured once a day, so it looks static, but behind the scenes the monitoring is more dynamic.

Count me in as a second to the question from rft.

I'd be interested if you have data to compare similar drives with stable tempretures against diurnal tempreture cycling.

I'd imagine you have fairly constant data centre type environments though which would confound analysis for such questions.

Re: Backblaze Drive Stats for Q3 2023

#67

Post by brnt »

ska wrote: post #52
brnt wrote: post #51

Earlier quoted context omitted.

Is moving the setpoint with the seasons, within tolerance of course, not a common energy savings method?

That makes more sense when you are housing people than servers, no?

Does it? Everybody wants to save energy. If the hardware can handle it, why not?

Re: Backblaze Drive Stats for Q3 2023

#68

Post by xurbax »

Netcob wrote: post #39
kstrauser wrote: post #29

Earlier quoted context omitted.

Conversely, I’ve had nothing but bad luck with WD the last few years, and my Seagates have been flawless. My simple rule is that all drives suck, and always have good backups.

My WD drives failed pretty consistently, so I'm now giving Seagate a try. Well, my main reason was that WD decided that just failing "naturally" after a few years wasn't enough, but that a drive having been on for 3 years should be considered the same as "failing" (communicated through WDDA), which led to Synology adopting that for a while. Not sure what the current state is of that, but I intend to swap drives when…

Well, for me, WD Reds seem to start to go bad at about 3 years, so...

Re: Backblaze Drive Stats for Q3 2023

#69

Post by patrakov »

gymbeaux wrote: post #62
gruez wrote: post #60

Earlier quoted context omitted.

Is that a realistic threat with AES-256 and randomly generated keys?

The local electronics recycling company where I live (US-FL) shreds hard drives by default and many of their enterprise clients apparently ask for it when they “donate” their old PowerEdge servers, NASes and whatnot. Now obviously the recycling company could try to discourage this in lieu of a 3 (or 7 or 100 or whatever) zero of the drives and then resell them as they do everything else they get “donated” to them… ma…

> Eventually, AES-256 can probably be brute-forced in a reasonable amount of time.

No. See https://security.stackexchange.com/questions/6141/amount-of-...

Time is not the bottleneck, energy is.

They invoke Landauer's principle which states that irreversible computation has an intrinsic cost in terms of energy per elementary operation, namely, k T ln(2) where k is the Boltzmann constant. Assuming brute-force search, more than 2^256 elementary operations would be needed, but that would require more energy than available if one converts the whole Sun's mass into energy.

Re: Backblaze Drive Stats for Q3 2023

#70

Post by adapiz »

xurbax wrote: post #68
Netcob wrote: post #39

Earlier quoted context omitted.

My WD drives failed pretty consistently, so I'm now giving Seagate a try. Well, my main reason was that WD decided that just failing "naturally" after a few years wasn't enough, but that a drive having been on for 3 years should be considered the same as "failing" (communicated through WDDA), which led to Synology adopting that for a while. Not sure what the current state is of that, but I intend to swap drives when…

Well, for me, WD Reds seem to start to go bad at about 3 years, so...

You might want to read this: https://arstechnica.com/gadgets/2023/06/clearly-predatory-we...

I had 4 WD Red 4 TB HDDs like WDC WD40EFRX and 2 out of them already failed SMART long tests and hat uncorrectable errors reported by the kernel after about 25000 hrs powered on. I've messed a lot with the drives bought 3 other used drives and it turned out that one of them had the same failure just undetected.

I was able to "fix" the issue by running testdisk in read-write mode forcing the disk to overwrite the bad sector. That's how I forcefully fix pending sectors on desktop drives. But it seems that WD Reds don't want to replace sectors because the data is still readable. The drive just needs a second or two.

I'm not happy with that but I'm also glad, I could confirm that's not an issue caused by my setup. One would say, I should replace the drive immediately but I trust in ZFS and my backups. I would put the drive on my shelve and maybe reuse it as temporary buffer storage because why would someone buy such a used drive for a high price? In my eyes, it's still okay.

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