原因:OpenPOWER Linux 開機過程所需的第一個開機磁區 PPC PReP Boot 無法安裝以 Software Raid 型式安裝,雖然在初次安裝系統時不會有任何影響,不過爾後第一顆磁碟因為發生故障,需要更換另一顆完全新的磁碟時,這樣雖然不會立即對系統產生影響,只要系統有做重啟,系統就會無法正常開機,原因是更換後的磁碟並沒有開機磁區。
解決方法就是:使第二顆磁碟也能做開機,步驟如本篇的教學。
TIPs:
PPC PReP Boot 這個專屬 IBM Power 機器的開機磁區其作用就像 x86 伺服器的 MBR。
確認目前系統可正常運作且第一顆磁碟的磁區狀態如下:
# fdisk -l /dev/sda Disk /dev/sda: 960.2 GB, 960197124096 bytes, 1875385008 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk label type: dos Disk identifier: 0x000e7231 Device Boot Start End Blocks Id System /dev/sda1 * 2048 22527 10240 41 PPC PReP Boot /dev/sda2 22528 2121727 1049600 fd Linux raid autodetect /dev/sda3 2121728 1875384319 936631296 fd Linux raid autodetect
說明:
sda1 Power 開機磁區 (這個需要複寫到第二顆磁碟)
sda2 Linux 開機磁區 /boot (已做 Raid 1 )
sda3 LVM 磁區 (已做 Raid6)
複寫 Power 開機磁區至第二顆磁碟 /sdb1
dd if=/dev/sda1 of=/dev/sdb1 bs=512 conv=noerror,sync
/dev/sdb 磁區清單
# fdisk -l /dev/sdb Disk /dev/sdb: 960.2 GB, 960197124096 bytes, 1875385008 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk label type: dos Disk identifier: 0x0003819f Device Boot Start End Blocks Id System /dev/sdb1 2048 22527 10240 41 PPC PReP Boot /dev/sdb2 22528 2121727 1049600 fd Linux raid autodetect /dev/sdb3 2121728 1875384319 936631296 fd Linux raid autodetect
說明:
sdb 與 sda 的磁區幾乎一樣,主要原因是這兩顆磁碟都被規劃成可開機磁碟。
不管是更換 sda 或 sdb 磁碟,更換後都需要手動建立開機磁區以及其他 raid 磁區。
以 /dev/sda 為例
fdisk /dev/sda 新增磁區 n > p > 1(default) > 2048(default) > 22527 n > p > 2 (default) > 22528 (default) > 2121727 n > p > 3 (default) > 2121728 (default) > 1875385007 (default) 設定磁區格式 t > 1 > 41 PPC PReP Boot t > 2 > fd Linux raid t > 3 > fd Linux raid 設定磁區#1 為開機磁區 a > 1 檢查磁區清單 p 寫入後離開 w
複寫開機磁區從 sdb 到 sda
dd if=/dev/sdb1 of=/dev/sda1 bs=512 conv=noerror,sync
檢視 Raid
# cat /proc/mdstat Personalities : [raid1] [raid6] [raid5] [raid4] md126 : active raid1 sdb2[1] 1049536 blocks super 1.0 [2/1] [_U] bitmap: 1/1 pages [64KB], 65536KB chunk md127 : active raid6 sdb3[1] sdd1[3] sde1[4] sdc[5] 2809500672 blocks super 1.2 level 6, 512k chunk, algorithm 2 [5/4] [_UUUU] bitmap: 1/1 pages [64KB], 65536KB chunk unused devices: <none> # mdadm --detail /dev/md126 /dev/md126: Version : 1.0 Creation Time : Mon Feb 20 23:30:01 2017 Raid Level : raid1 Array Size : 1049536 (1024.94 MiB 1074.72 MB) Used Dev Size : 1049536 (1024.94 MiB 1074.72 MB) Raid Devices : 2 Total Devices : 1 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Feb 24 19:55:16 2017 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Name : localhost.localdomain:boot UUID : 1b78d1ea:f5380532:4fe25553:20ef8396 Events : 44 Number Major Minor RaidDevice State - 0 0 0 removed 1 8 18 1 active sync /dev/sdb2 # mdadm --detail /dev/md127 /dev/md127: Version : 1.2 Creation Time : Mon Feb 20 23:30:10 2017 Raid Level : raid6 Array Size : 2809500672 (2679.35 GiB 2876.93 GB) Used Dev Size : 936500224 (893.12 GiB 958.98 GB) Raid Devices : 5 Total Devices : 4 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Feb 24 14:42:10 2017 State : clean, degraded Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : left-symmetric Chunk Size : 512K Name : localhost.localdomain:pv00 UUID : f7a62cb2:b269daa9:29f8025f:6fcef40f Events : 4769 Number Major Minor RaidDevice State - 0 0 0 removed 1 8 19 1 active sync /dev/sdb3 5 8 32 2 active sync /dev/sdc 3 8 49 3 active sync /dev/sdd1 4 8 65 4 active sync /dev/sde1
重建 Raid
# fdisk -l /dev/sda Disk /dev/sda: 960.2 GB, 960197124096 bytes, 1875385008 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk label type: dos Disk identifier: 0x000e7231 Device Boot Start End Blocks Id System /dev/sda1 * 2048 22527 10240 41 PPC PReP Boot /dev/sda2 22528 2121727 1049600 fd Linux raid autodetect /dev/sda3 2121728 1875385007 936631640 fd Linux raid autodetect # mdadm /dev/md126 --add /dev/sda2 # mdadm /dev/md127 --add /dev/sda3
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