BTRFS NAS惡夢~~Phoronix: BTRFS RAID5將出現重大問題

Btrfs RAID 5/6 Code Found To Be Very Unsafe & Will Likely Require A Rewrite
BTRFS RAID5/6代碼發現是非常不安全的&很可能需要重寫

It turns out the RAID5 and RAID6 code for the Btrfs file-system's built-in RAID support is faulty and users should not be making use of it if you care about your data.
原來,RAID5和RAID6代碼,增加了Btrfs文件系統內置的RAID支持有故障,如果你關心你的數據的用戶不應該利用它。

There has been this mailing list thread since the end of July about Btrfs scrub recalculating the wrong parity in RAID5. The wrong parity and unrecoverable errors has been confirmed by multiple parties. The Btrfs RAID 5/6 code has been called as much as fatally flawed -- "more or less fatally flawed, and a full scrap and rewrite to an entirely different raid56 mode on-disk format may be necessary to fix it. And what's even clearer is that people /really/ shouldn't be using raid56 mode for anything but testing with throw-away data, at this point. Anything else is simply irresponsible."
已經有自7月約增加了Btrfs擦洗重新計算在RAID5錯誤校驗結束這個郵件列表線程。錯誤的奇偶校驗和不可恢復的錯誤已被多方證實。在增加了Btrfs RAID5/6的代碼被稱為不亞於致命的缺陷 - “或多或少存在致命的缺陷,以及全面的報廢和重寫,以一種完全不同的方式raid56的磁盤格式可能需要修復它,什麼是更清楚的是,人/真的/不應該使用raid56模式什麼,但有扔掉的數據測試,在這一點上,還有什麼簡直是不負責任的。“

So hopefully you aren't making use of any Btrfs RAID 5/6 support as it turns out to be in very bad shape and may even be ifdef'ed out of the mkfs code. Unfortunately it could take some time to fix especially with the potential for a format change being necessary to address the problem. The RAID56 wiki page has already been updated so users don't accidentally try one of these Btrfs RAID levels.
所以希望你沒有充分利用,因為它原來是在非常惡劣的形狀,甚至可以ifdef'ed出的mkfs的任何代碼增加了Btrfs RAID5/6支持。不幸的是,可能需要一些時間與特別修復對於格式變化是必要的,以解決問題的潛力。該RAID56維基頁面已經更新,因此用戶不小心嘗試這些增加了Btrfs RAID級別中的一個。


資料來源:
Michael Larabel, Btrfs RAID 5/6 Code Found To Be Very Unsafe & Will Likely Require A Rewrite. Phoronix, 5 August 2016.
https://phoronix.com/scan.php?pa ... trfs-RAID-56-Is-Bad

Google 翻譯:
https://translate.google.com.hk/?hl=zh-TW&tab=wT

btrfs raid5 is not yet for production
i don't see any damage to user unless ... those smarties use it on production ...

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外國網民回應(EluSiOn, 2016):

btrfs on lvm 上面比較慢的出處是 btrfs 的官網 https://btrfs.wiki.kernel.org/index.php/FAQ
Btrfs on lvm The above is relatively slow source btrfs official website https://btrfs.wiki.kernel.org/index.php/FAQ



官網的字眼是非常重的... ineffective 是一個超級負面的字 (not producing any significant or desired effect)
Government network specifically shaped eye by all means normal weight basis ... ineffective Shi one than class negative surface specific character (not producing any significant or desired effect)

寫入慢的問題在 nvme ssd, 10 gbe 網卡的企業環境下, 會成為瓶頸, 這個就是為什麼不建議. 在家用情況下因為 1gbe 是不會有效能的問題的. 但是如果碰上 rebuild 是... 還是會需要搭配 運行 /sbin/fsck.ext3 /sbin/fsck.ext4 /sbin/fsck.xfs 這部分... 不同的檔案格式還是有影響的啦 所以連 rebuild 都會有被影響到... 這個就變成安全風險係數的問題了.
Write slow problem In nvme ssd, 10 gbe NIC business environment, it will become a bottleneck, this is why not recommended. In the case of home because 1gbe is not a problem, but if the impact is to rebuild. . Will still need to run with /sbin/fsck.ext3 /sbin/fsck.ext4 /sbin/fsck.xfs this part ... different file formats or influential friends so even rebuild will be affected ... this It becomes a safety risk factor of the problem.

我覺得重點在於為什麼 Synology 使用了一個架構是 BTRFS 開發團隊不推薦 (雖然也不反對) 的架構? 大部分都應該使用原廠或是開發團隊大力推薦的使用模式以及架構才對.
I think the focus is on why Synology uses a schema that the BTRFS development team does not recommend (though not against) architectures. Most should use the usage patterns and architectures that are strongly recommended by the original or development team.

資料來源:
source:
網路儲存裝置 - BTRFS 有雷 - 目前不適用於 RAID5/6 - 電腦討論區 - Mobile01:
Network Storage - BTRFS with Ray - Not Currently Available for RAID5 / 6 - PC Forum - Mobile01:
http://www.mobile01.com/topicdetail.php?f=494&t=4936762

Google 翻譯:
Google Translate:
https://translate.google.com.hk/?hl=zh-TW&tab=wT

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如果有興趣, 直接睇原討論 thread.
http://www.mobile01.com/topicdet ... 62&p=1#61809583

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回覆 4# pctine

原post雖然不太明白, 但是好像很厲害

EluSiOn:

我相信 pctine 的測試... 因為... 沒有必要這樣子搞...
I believe pctine test ... because ... there is no need to do this ...

我是想要測試更加完整一些... 畢竟最後 Synology 不說話的話... 那麼就是能夠拿出數據的人話最大.
I want to test more complete ... After all, the last thing Synology does not speak ... then it is able to come up with the data, then the largest

我會讓 OS 碟在單獨的 ssd 上面. 然後其它的 hdd做成 storage pool 的, 這樣子更加可以顯現 storage pool 因為不同的架構的效能.
I will let the OS disk in a separate ssd above. Then the other hdd made storage pool, so that more can show storage pool because the performance of different architectures


資料來源:
source:
網路儲存裝置 - BTRFS 有雷 - 目前不適用於 RAID5/6 - 電腦討論區 - Mobile01:
Network Storage - BTRFS with Ray - Not Currently Available for RAID5 / 6 - PC Forum - Mobile01:
http://www.mobile01.com/topicdet ... 62&p=5#61829086

Google 翻譯:
Google Translate:
https://translate.google.com.hk/?hl=zh-TW&tab=wT

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回覆  pctine

原post雖然不太明白, 但是好像很厲害

資料來源:
source:
網路儲存裝置 - BTRFS 有雷 -  ...
dmm.co.jp 發表於 2016-9-29 23:42


"BTRFS 有雷 - 目前不適用於 RAID5/6"
>>>> 呢個應該係 "原生BTRFS 有雷 - 目前不適用於 RAID5/6"

"在使用 Synology NAS 的人們真的請注意. btrfs 目前不適用於 RAID5/6. 它計算 parity 的 ..."
>>>> Synology NAS 唔係行 "原生 BTRFS RAID5/6"

https://www.synology.com/zh-tw/k ... stem_on_SynologyNAS

冇錯. 開版原 PO 技術真嘅好塞咧, 不過引用資料唔係正確嘅.

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不如 off 咗個 Google Translate 啦,一時中變英一時英變中,D 翻譯古古怪怪睇到我一頭煙,英文原文就貼英文,中文原文貼返中文等大家自己睇算啦

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本帖最後由 s84292 於 2016-9-30 23:56 編輯
外國網民回應(EluSiOn, 2016):

btrfs on lvm 上面比較慢的出處是 btrfs 的官網
Btrfs on lvm The above i ...
dmm.co.jp 發表於 2016-9-28 23:51


Synology 並沒有使用BTRFS在RAID 5/6系統上,
Synology底層都係LINUX RAID,
佢地就係因為發現BTRFS唔適合先至改用呢種比較轉接的方案,
以少量性能換取穩定性,但又能同時保留BTRFS的優點

就好似係WINDOWS REFS 套在底層RAID系統組成存貯池
然後再放一個虛擬硬碟檔案(VHD)行NTFS系統咁

(REFS 對比NTFS有性能優勢,內建復原及大幅度改進磁碟結構可靠性,
但是不支援重複資料刪除、寫時快照和壓縮->NTFS支援重複資料刪除和壓縮,
而且缺乏還原及API第三方支援,所以這樣去取長補短)

順便一提重複資料刪除真是好東西, 我公司部WINDOWS SERVER 2012R2,放文件檔案,慳70%位...
2TB文件,實際食唔到600GB,幾時Synology NAS都搞個類似功能出黎,
NAS 要有重複資料刪除要5萬以上先有...

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Synology 並沒有使用BTRFS在RAID 5/6系統上,
Synology底層都係LINUX RAID,
佢地就係因為發現BTRFS唔 ...
s84292 發表於 2016-9-30 23:38


Synology有deduplication, 但係只限用於backup

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