幹壞事是進步最大的原動力
Backblaze 釋出了 2023Q2 的硬碟報告：「Backblaze Drive Stats for Q2 2023」。
看硬碟數量有破千顆的會比較準確，跟以前的趨勢差不多，HGST 與改牌到 WDC 的硬碟在第一梯隊，再來是 Toshiba，然後是 Seagate：
特別被拿出來講的是 0% 死亡率的：
前面三顆 Drive Days 都夠高，還可以維持 0% 死亡率，算是可以選擇的型號？
另外比較特別的是 8TB 與 10TB 硬碟的死亡率比平均值高不少，不過文章裡面有提到 10TB 因為量太少所以跳過 (可能還在統計誤差的範圍)：
Given there are relatively few 10TB drives (1,124) versus 8TB drives (24,891), let’s dig deeper into the 8TB drives models.
而 8TB 的資料可以看到這幾顆的狀況：
這邊算是提供要避開的型號？
前幾天 Backblaze 放了 2020 年的回顧資料出來：「Backblaze Hard Drive Stats for 2020」。
整體的 AFR (Annualized Failure Rate) 在 0.93% 左右，而如果照品牌拆開，HGST 的數字依然是最漂亮的 (雖然他現在是 WD 的品牌)，大約在 0.36% 左右 (111/(1083774+4663049+372000+820272+275779+3968475))，Toshiba 次之，大約低了平均值一些落在 0.89%，而 Seagate 光是看就就知道會超過 1%...
官方有提到，低於 250,000 drive days 以下的數據僅供參考，因為資料量太少，在統計上無法提供結論：
For drives which have less than 250,000 drive days, any conclusions about drive failure rates are not justified. There is not enough data over the year-long period to reach any conclusions. We present the models with less than 250,000 drive days for completeness only.
然後 WD 本家的硬碟回到戰線了，記得之前基本上算是被唾棄 XDDD
另外一張表則是講到這三年的情況，可以看出來 2020 年的 AFR 數字降了不少，裡面也解釋了為什麼 (看起來就是活下來的穩下來了...)：
The answer: It was a group effort. To start, the older drives: 4TB, 6TB, 8TB, and 10TB drives as a group were significantly better in 2020, decreasing from a 1.35% AFR in 2019 to a 0.96% AFR in 2020. At the other end of the size spectrum, we added over 30,000 larger drives: 14TB, 16TB, and 18TB, which as a group recorded an AFR of 0.89% for 2020. Finally, the 12TB drives as a group had a 2020 AFR of 0.98%. In other words, whether a drive was old or new, or big or small, they performed well in our environment in 2020.
Backblaze 丟出去年的報告了：「Backblaze Hard Drive Stats for 2019」。
WD/HGST 的還是最耐用，再來是 Toshiba 的，最後是 Seagate 的。
不過有一些硬碟沒有列到表上，像是「Seagate 16 TB Drives」這組因為 2019Q4 才剛裝上去，所以才 1440 drive days，因此還沒到門檻所以沒放進報告，但就 Backblaze 測試起來看起來是個好的開始：
In Q4 2019 we started qualifying Seagate 16 TB drives, model: ST16000NM001G. As of the end of Q4 we had 40 (forty) drives in operation, with a total of 1,440 drive days—well below our 5,000 drive day threshold for Q4, so they didn’t make the 2019 chart. There have been 0 (zero) failures through Q4, making the AFR 0%, a good start for any drive. Assuming they continue to pass our drive qualification process, they will be used in the 12 TB migration project and to add capacity as needed in 2020.
再來是把 2017/2018/2019 擺在一起看：
馬上可以看到的是 AFR 上升了不少，一個是因為 8TB 系列的硬碟進入中年期，另外是 Seagate 12TB 硬碟的問題：
The total AFR for 2019 rose significantly in 2019. About 75% of the different drive models experienced a rise in AFR from 2018 to 2019. There are two primary drivers behind this rise. First, the 8 TB drives as a group seem to be having a mid-life crisis as they get older, with each model exhibiting their highest failure rates recorded. While none of the rates is cause for worry, they contribute roughly one fourth (1/4) of the drive days to the total, so any rise in their failure rate will affect the total. The second factor is the Seagate 12 TB drives, this issue is being aggressively addressed by the 12 TB migration project reported on previously.
所以大原則還是跟以前差不多，沒有時間特別研究的話就先往 WD/HGST 這邊找...
Backblaze 照慣例發表了 2018 Q2 的硬碟狀況：「Hard Drive Stats for Q2 2018」。可以看出來他們基本上只用 Seagate 與 HGST 了，其他的應該是嘗試性質：
第二張因為把信心區間標出來，會更清楚：
WD 差了一大截，所以現在消費級的硬碟會選 Seagate 或是 HGST？
Backblaze 針對 2016 年的硬碟損耗狀況進行分析，這次因為剛好是跨年，所以包括了 2016Q4 與 2016 全年度的資料：「Backblaze Hard Drive Stats for 2016」。
大家比較有興趣的重點應該是全年度的廠牌比較：
依照往例，Backblaze 每一季結束後不久會放出上一季的硬碟故障率報告：「What Can 49,056 Hard Drives Tell Us? Hard Drive Reliability Stats for Q3 2015」。
如果仔細看的話，小硬碟中 Seagate 的死亡率還是很高 (尤其是 ST1500DL003 與 ST3000DM001 這兩顆驚人的數字)，而大硬碟 (i.e. 4TB 以上) 都還算合理範圍。
值得提的是，其中 HGST 的硬碟死亡率比起其他家低了不少？
Backblaze 這次丟出了 2015 年上半年的數據，標題雖然是寫 2015Q2，但文章裡有半年的統計資料：「Hard Drive Reliability Stats for Q2 2015」。
雖然都知道某公司的產品故障率偏高，但這樣是有仇嗎 XDDD
這是統計資料：
另外是 4TB 的歷史紀錄，右邊兩家的數字有點少啊，不過 45 顆硬碟壞一顆不就 2.x% 了嗎，這數字到底是怎麼出來的啊：
Backblaze 針對 3TB 硬碟繼續黑 Seagate... XDDD：「CSI: Backblaze – Dissecting 3TB Drive Failure」。
前面的數量比較不好懂，用百分比比較容易了解：
文章裡還討論了外接或內接的情況，最後猜測的結論是，Seagate 的這個 3TB 型號的品質特別差，因為 4TB 就正常許多：
While this particular 3TB model had a painfully high rate of failure, subsequent Seagate models such as their 4TB drive, model: ST4000DM000, are performing well with an annualized 2014 failure rate of just 2.6% as of December 31, 2014. These drives come with 3-year warranties and show no signs of hitting the wall.
今年年初 (一月) 的時候發表過一次「各家硬碟的耐用程度...」引起爭議厚的最新力做，九月再發表一次：「Hard Drive Reliability Update – Sep 2014」。
灰色部份是一月的數據，其他顏色是九月的數據。文中有考慮是否要換成企業級的硬碟 (enterprise drives)，但兩個評估的答案是否定的。
第一個評估是成本考量，就算一般硬碟以三年保固期有 15% 的 failure rate，相較於企業級 0% failure rate 計算 (於是直接算成 10 年)，成本是不划算的：
Today on Amazon, a Seagate 3 TB “enterprise” drive costs $235 versus a Seagate 3 TB “desktop” drive costs $102. Most of the drives we get have a 3-year warranty, making failures a non-issue from a cost perspective for that period. However, even if there were no warranty, a 15% annual failure rate on the consumer “desktop” drive and a 0% failure rate on the “enterprise” drive, the breakeven would be 10 years, which is longer than we expect to even run the drives for.
更何況企業級硬碟的情況根本沒什麼差：
The assumption that “enterprise” drives would work better than “consumer” drives has not been true in our tests. I analyzed both of these types of drives in our system and found that their failure rates in our environment were very similar — with the “consumer” drives actually being slightly more reliable.
