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Annual Hard Drive Reliability Report: 8TB, HGST Disks Top Chart Racking Up 45 Years Without Failure (arstechnica.com)
Online backup solution provider Backblaze has released its much-renowned, annual hard drives reliability and failure report. From a report on ArsTechnica: The company uses self-built pods of 45 or 60 disks for its storage. Each pod is initially assembled with identical disks, but different pods use different sizes and models of disk, depending on age and availability. The standout finding: three 45-disk pods using 4TB Toshiba disks, and one 45-disk pod using 8TB HGST disks, went a full year without a single spindle failing. These are, respectively, more than 145 and 45 years of aggregate usage without a fault. The Toshiba result makes for a nice comparison against the drive's spec sheet. Toshiba rates that model as having a 1-million-hour mean time to failure (MTTF). Mean time to failure (or mean time between failures, MTBF -- the two measures are functionally identical for disks, with vendors using both) is an aggregate property: given a large number of disks, Toshiba says that you can expect to see one disk failure for every million hours of aggregated usage. Over 2016, those disks accumulated 1.2 million hours of usage without failing, healthily surpassing their specification. [...] For 2016 as a whole, Backblaze saw its lowest ever failure rate of 1.95 percent. Though a few models remain concerning -- 13.6 percent of one older model of Seagate 4TB disk failed in 2016 -- most are performing well. Seagate's 6TB and 8TB models, in contrast, outperform the average. Improvements to the storage pod design that reduce vibration are also likely to be at play.
The bathtub curve is real, and if you follow BackBlaze tips, they show that years 2-4 are usually exceptional in terms of reliability.
My recommendation is to buy the NAS/SAN/POD/Whatever and spin it up for 3 months, then put it into production and then wait 42 months. After that, start planning and when the next drive fails in the 42-48 month range, start the purchasing process (depending on lead time needed), get it installed, wait 3 months to get early failures out of the way than transfer data ... wash/rinse/repeat. You'll get close to five years between purchase and retirement, with a bit of overlap between versions.
If you have several decks of drives, you can get a reasonable cycle going, and it becomes second nature. Data loss is not an option.
Agent K: A *person* is smart. People are dumb, stupid, panicky animals, and you know it.
The bathtub curve is real
This Backblaze report, previous Backblaze reports, and the Google logitudinal disk reliability study, have all found that the "bathtub curve" is a myth. HDDs do not have high early failure rates, nor does the failure rate suddenly rise after a set period of time.
Another myth that these studies have debunked is that HDDs do better if kept cool. Actually, failure rates are lower for disks kept at the higher end of the rated temperatures. This is one reason that Google runs "hot" datacenters today, with ambient temps over 100F.
I find it hard to believe. It isn't measuring 45 years worth of things like metal fatigue, material decay or degeneration, wear and tear etc.
For spinning disks, factors that do not materialize in the first few years and thus can't be determined from an aggregated short time test include (but are not limited to)
- demagnetization of fixed magnets (leads to write failures)
- magnetization of paramagnetic materials (leads to bit rot)
- wear on ball bearings (leads to all kinds of fatal crashes)
- accretion of and contamination of lubrication (leads to sticktion)
Based on my own experience as a long term sysadmin, the quality and longevity of drives go up and down. Late 1990s drives were bad, early 2000s were good, late 2000s were bad, early 2010s were good, and now it's pretty bad again. It's not just vendor specific, because vendors seem to adjust to each other to arrive at common price/quality point. Sure, there are exceptions, like the Deathstars, but overall, I think the drives tend to be similar in longevity not so much based on brand, but what generation they are.
Ps a clear example of this is that all manufacturers make drives with different numbers of platters. A drive with 5 platters is FAR more likely to fail than a drive with 1 platter. They may be made by the same manufacturer, but the 5-platter model is at least 5 times as likely to fail (platters interfere with each other).