我正在使用包含多個 LV 的單一 VG 來恢復 mdadm RAID 1 上的 PV。
底層設備有幾個壞扇區（一個只有幾個，另一個則非常多），而一個愚蠢的拼字錯誤使得必須透過 grep 遍歷設備來恢復 LVM 配置。幸運的是我找到了它，恢復後的配置看起來和原來的配置一樣。
唯一的問題是邏輯磁碟區沒有有效的檔案系統。使用 e2sl，我發現目標檔案系統的超級區塊之一位於錯誤的邏輯磁碟區中。遺憾的是我不知道如何修正或規避這個問題。
root@rescue ~/e2sl # ./ext2-superblock -d /dev/vg0/tmp | grep 131072000
Found: block 20711426 (cyl 1369, head 192, sector 50), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
root@rescue ~/e2sl # ./ext2-superblock -d /dev/vg0/home | grep 131072000
Found: block 2048 (cyl 0, head 32, sector 32), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 526336 (cyl 34, head 194, sector 34), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 1050624 (cyl 69, head 116, sector 36), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 1574912 (cyl 104, head 38, sector 38), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 2099200 (cyl 138, head 200, sector 40), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 6293504 (cyl 416, head 56, sector 56), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 6817792 (cyl 450, head 218, sector 58), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 12584960 (cyl 832, head 81, sector 17), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 20973568 (cyl 1387, head 33, sector 49), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 32507904 (cyl 2149, head 238, sector 30), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 63440896 (cyl 4195, head 198, sector 22), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
Found: block 89655296 (cyl 5929, head 139, sector 59), 131072000 blocks, 129988776 free blocks, 4096 block size, (null)
^C
我感覺距離再次訪問我的檔案系統以恢復一些未備份的資料僅一步之遙。
LVM配置：
root@rescue ~ # pvs
PV VG Fmt Attr PSize PFree
/dev/md1 vg0 lvm2 a-- 2.71t 767.52g
root@rescue ~ # vgs
VG #PV #LV #SN Attr VSize VFree
vg0 1 5 0 wz--n- 2.71t 767.52g
root@rescue ~ # lvs
LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert
backup vg0 -wi-a--- 500.00g
container vg0 -wi-a--- 500.00g
home vg0 -wi-a--- 500.00g
root vg0 -wi-a--- 500.00g
tmp vg0 -wi-a--- 10.00g
VG配置：
# Generated by LVM2 version 2.02.95(2) (2012-03-06): Sun Oct 13 23:56:33 2013
contents = "Text Format Volume Group"
version = 1
description = "Created *after* executing 'vgs'"
creation_host = "rescue" # Linux rescue 3.10.12 #29 SMP Mon Sep 23 13:18:39 CEST 2013 x86_64
creation_time = 1381701393 # Sun Oct 13 23:56:33 2013
vg0 {
id = "7p0Aiw-pBpd-rn6Y-geFb-jyZe-gide-Anc9ag"
seqno = 19
format = "lvm2" # informational
status = ["RESIZEABLE", "READ", "WRITE"]
flags = []
extent_size = 8192 # 4 Megabytes
max_lv = 0
max_pv = 0
metadata_copies = 0
physical_volumes {
pv0 {
id = "GBIwI4-AxBa-6faf-aLfB-UZiP-iSS9-FaOrhH"
device = "/dev/md1" # Hint only
status = ["ALLOCATABLE"]
flags = []
dev_size = 5824875134 # 2.71242 Terabytes
pe_start = 384
pe_count = 711044 # 2.71242 Terabytes
}
}
logical_volumes {
root {
id = "1e3gvq-IJnX-Aimz-ziiY-zucE-soCO-YU2ayp"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 128000 # 500 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 0
]
}
}
tmp {
id = "px8JAy-JnkP-Amry-uHtf-lCUB-rfdx-Z8y11y"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 2560 # 10 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 128000
]
}
}
home {
id = "e0AZbd-22Ss-RLrF-TgvF-CSDN-Nw6w-Gj7dal"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
segment_count = 1
segment1 {
start_extent = 0
extent_count = 128000 # 500 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 130560
]
}
}
backup {
id = "ZXNcbK-gYKj-LJfm-f193-Ozsi-Rm3Y-kZL37c"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
creation_host = "new.bountin.net"
creation_time = 1341852222 # 2012-07-09 18:43:42 +0200
segment_count = 1
segment1 {
start_extent = 0
extent_count = 128000 # 500 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 258560
]
}
}
container {
id = "X9wheh-3ADB-Fiau-j7SR-pcH9-hXne-K2NVAc"
status = ["READ", "WRITE", "VISIBLE"]
flags = []
creation_host = "new.bountin.net"
creation_time = 1341852988 # 2012-07-09 18:56:28 +0200
segment_count = 1
segment1 {
start_extent = 0
extent_count = 128000 # 500 Gigabytes
type = "striped"
stripe_count = 1 # linear
stripes = [
"pv0", 386560
]
}
}
}
}
答案1
對於任何有類似問題的人：
我使用 e2sl [1] 實際上直接從 RAID 設備之一查找檔案系統的候選對象，並使用循環設備 [2] 跳過 LVM 和軟體 RAID 來安裝檔案系統。我必須稍微調整一下偏移量（超級區塊位置到分割區開頭的偏移量為 1KB！），但最終我設法做到了。
從那裡開始，救援就變得非常簡單：將循環設備安裝到安裝點，然後所有內容都可以複製。
[2] mount --loop 並查看 losetup