Backblaze 的 2015 Q3 硬碟故障率報告

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 2015 年上半年的硬碟穩定度報告出爐了... (又黑了某公司一把)

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 的 3TB 硬碟故障分析

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.

Backblaze 用 SMART 的資料推算硬碟故障可能性

Backblaze 的「Hard Drive SMART Stats」這篇文章裡面提到了用 S.M.A.R.T. 的資料交叉分析硬碟存活的比率。

比較有趣的是對 Power_Cycle_Count 這個數據的解讀:

We’re not sure whether this is because cycling the power is bad for the drive, or because working on the pods is bad for the drives, or because “new” drives have flaws that are exposed during the first few dozen power cycles and then things settle down.

再對照其他幾張與 Power_Cycle_Count 相關的圖,通電次數看不出跟存活率有絕對關係 :p

Backblaze 再次發表各家硬碟耐用程度...

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.