我有一個帶有 mdadm 設定的 5 驅動器軟體 raid6（2 個奇偶校驗驅動器），但有一個驅動器出現故障。我訂購了更換件，當我關閉機器電源以將故障驅動器更換為新驅動器時，另一個驅動器同時發生故障（完全失效）。因此，現在有 3 個舊驅動器有數據，1 個新驅動器正在重建，還有 1 個驅動器遺失。
然後我注意到重建速度非常慢，資料只能處理 100 kb/s 左右。之前的重建運行速度約為 100 MB/s！我決定購買一台帶有新驅動器的 Synology 設備，並在還可以的時候複製盡可能多的資料。它已經運行了 2 個月，我已經能夠複製幾個 TB 的數據，但還有幾個 TB 的數據需要複製，以這個速度，還需要 6 個月才能完成。
新 NAS (Synology) 上的資料正常，到目前為止沒有資料遺失！我希望我能做點什麼來讓它跑得更快。錯誤日誌表明它在特定驅動器（sdd）上失敗，但也許有一個設定會告訴它“更快地失敗”，以便它複製得更快，因為它實際上並沒有失敗？日誌如下：
cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid6 sdf1[5] sdb1[0] sdc1[1] sdd1[2]
17581168128 blocks super 1.2 level 6, 512k chunk, algorithm 2 [5/3] [UUU__]
[>....................] recovery = 0.4% (24696932/5860389376) finish=584364702.6min speed=0K/sec
unused devices: <none>
/var/log/messages 的尾部
Dec 16 11:29:47 [localhost] kernel: ata4.00: status: { DRDY ERR }
Dec 16 11:29:47 [localhost] kernel: ata4.00: error: { UNC }
Dec 16 11:29:47 [localhost] kernel: ata4: hard resetting link
Dec 16 11:29:47 [localhost] kernel: ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Dec 16 11:29:47 [localhost] kernel: ata4.00: configured for UDMA/133
Dec 16 11:29:47 [localhost] kernel: sd 3:0:0:0: [sdd] tag#24 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
Dec 16 11:29:47 [localhost] kernel: sd 3:0:0:0: [sdd] tag#24 Sense Key : Medium Error [current] [descriptor]
Dec 16 11:29:47 [localhost] kernel: sd 3:0:0:0: [sdd] tag#24 Add. Sense: Unrecovered read error - auto reallocate failed
Dec 16 11:29:47 [localhost] kernel: sd 3:0:0:0: [sdd] tag#24 CDB: Read(16) 88 00 00 00 00 00 02 87 64 50 00 00 00 40 00 00
Dec 16 11:29:47 [localhost] kernel: blk_update_request: I/O error, dev sdd, sector 42427472
Dec 16 11:29:47 [localhost] kernel: raid5_end_read_request: 5 callbacks suppressed
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425424 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425432 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425440 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425448 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425456 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425464 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425472 on sdd1).
Dec 16 11:29:47 [localhost] kernel: md/raid:md0: read error not correctable (sector 42425480 on sdd1).
Dec 16 11:29:47 [localhost] kernel: ata4: EH complete
Dec 16 11:29:51 [localhost] kernel: ata4.00: exception Emask 0x0 SAct 0x10000000 SErr 0x0 action 0x0
Dec 16 11:29:51 [localhost] kernel: ata4.00: irq_stat 0x40000008
Dec 16 11:29:51 [localhost] kernel: ata4.00: failed command: READ FPDMA QUEUED
Dec 16 11:29:51 [localhost] kernel: ata4.00: cmd 60/38:e0:30:b8:f5/00:00:02:00:00/40 tag 28 ncq 28672 in#012 res 41/40:00:30:b8:f5/00:00:02:00:00/00 Emask 0x409 (media error) <F>
答案1
因此，有幾個關於超級用戶的貼文與此類似，但都沒有得到回應。這是因為你應該先使用 ddrescue 來修復音量，然後 rsync 就可以了。
https://raid.wiki.kernel.org/index.php/Recovering_a_failed_software_RAID