Mdadm
mdadm raid5：所有磁碟都顯示為備用
我為我的 raid 5 的 4 個磁碟中的 2 個拔掉了電源插頭。從那以後它無法啟動。即使使用 –run –force、–readwrite 等。我很快就看到了，所以數據不應該（太多）損壞。
這是詳細資訊：
/dev/md2: Version : 1.2 Creation Time : Mon Oct 28 14:46:16 2019 Raid Level : raid5 Used Dev Size : 243138560 (231.88 GiB 248.97 GB) Raid Devices : 4 Total Devices : 4 Persistence : Superblock is persistent Update Time : Thu Apr 9 20:37:49 2020 State : active, FAILED, Not Started Active Devices : 0 Working Devices : 4 Failed Devices : 0 Spare Devices : 4 Layout : left-symmetric Chunk Size : 512K Consistency Policy : unknown Number Major Minor RaidDevice State - 0 0 0 removed - 0 0 1 removed - 0 0 2 removed - 0 0 3 removed - 8 50 3 spare rebuilding /dev/sdd2 - 8 34 1 spare rebuilding /dev/sdc2 - 8 18 2 spare rebuilding /dev/sdb2 - 8 2 0 spare rebuilding /dev/sda2現在我可以簡單地用 sudo mdadm –create /dev/md2 –level=5 –raid-devices=4 –chunk=512 /dev/sdd2 /dev/sdb2 /dev/sda2 /dev 重新創建陣列/sdc2 ？我應該關心驅動器的順序，對吧？
如要求，–examine 的輸出：
/dev/sda2: Magic : a92b4efc Version : 1.2 Feature Map : 0x8b Array UUID : 0956b1a2:4ed1052a:016155a1:940db446 Name : raspberrypi3:2 Creation Time : Mon Oct 28 14:46:16 2019 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 486277120 (231.88 GiB 248.97 GB) Array Size : 729415680 (695.63 GiB 746.92 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Recovery Offset : 36416 sectors Unused Space : before=262056 sectors, after=0 sectors State : clean Device UUID : da9f05d3:64d47a14:78eedb5e:dd69151c Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 9 20:37:49 2020 Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present. Checksum : ccf72dc4 - correct Events : 8802 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 0 Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing) /dev/sdb2: Magic : a92b4efc Version : 1.2 Feature Map : 0x8b Array UUID : 0956b1a2:4ed1052a:016155a1:940db446 Name : raspberrypi3:2 Creation Time : Mon Oct 28 14:46:16 2019 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 486277120 (231.88 GiB 248.97 GB) Array Size : 729415680 (695.63 GiB 746.92 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Recovery Offset : 36416 sectors Unused Space : before=262056 sectors, after=0 sectors State : active Device UUID : e709a92a:c10f1949:c9868538:f5cc2acc Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 9 20:37:49 2020 Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present. Checksum : e2f7ce99 - correct Events : 8802 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 2 Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing) /dev/sdc2: Magic : a92b4efc Version : 1.2 Feature Map : 0x8b Array UUID : 0956b1a2:4ed1052a:016155a1:940db446 Name : raspberrypi3:2 Creation Time : Mon Oct 28 14:46:16 2019 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 486277120 (231.88 GiB 248.97 GB) Array Size : 729415680 (695.63 GiB 746.92 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Recovery Offset : 36416 sectors Unused Space : before=262056 sectors, after=0 sectors State : active Device UUID : e1c4f361:af07c81c:1e6b8f72:962869a5 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 9 20:37:49 2020 Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present. Checksum : 139c176 - correct Events : 8801 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 1 Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing) /dev/sdd2: Magic : a92b4efc Version : 1.2 Feature Map : 0x8b Array UUID : 0956b1a2:4ed1052a:016155a1:940db446 Name : raspberrypi3:2 Creation Time : Mon Oct 28 14:46:16 2019 Raid Level : raid5 Raid Devices : 4 Avail Dev Size : 486277120 (231.88 GiB 248.97 GB) Array Size : 729415680 (695.63 GiB 746.92 GB) Data Offset : 262144 sectors Super Offset : 8 sectors Recovery Offset : 36416 sectors Unused Space : before=262056 sectors, after=0 sectors State : active Device UUID : ce27edb8:365853c7:e0434b32:5ae01e33 Internal Bitmap : 8 sectors from superblock Update Time : Thu Apr 9 20:37:49 2020 Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present. Checksum : 50300573 - correct Events : 8801 Layout : left-symmetric Chunk Size : 512K Device Role : Active device 3 Array State : AAAA ('A' == active, '.' == missing, 'R' == replacing)
因此，經過一周的各種嘗試，答案是壞塊列表。在硬故障之前，raid 陣列開始將所有對底層磁碟的訪問添加為壞塊。因此，即使通過強制陣列以“迴聲”開頭，也可以很好地組裝磁碟
$$ X,Y,Z,W $$| sudo tee /sys/block/md2/md/dev-sd$$ a,b,c,d $$2/slot" 訪問 /dev/mdX 時會導致 I/O 錯誤。 所以我用“sudo mdadm –assemble –update=force-no-bbl /dev/md2 /dev/sda2 /dev/sdd2 /dev/sdc2 /dev/sdb2”強制陣列開始忽略阻止列表。瘋狂的是沒有任何線索的原因。我剛剛遇到“dev md2 上的緩衝區 I/O 錯誤，邏輯塊 0，非同步頁面讀取”。這導致網路上什麼都沒有……