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使用 dd 进行逻辑卷备份和恢复

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使用 dd 进行逻辑卷备份和恢复

我已经为逻辑卷创建了快照，如下所示：

sudo lvcreate -v -s -L 100M -n lv2_snap /dev/vg1/lv2

我能够安装该快照，检查文件，看起来不错。

然后，对快照进行磁盘转储：

sudo dd if=/dev/vg1/lv2_snap of=lv2_snap.dd

之后，我尝试从磁盘转储中恢复：

sudo dd if=lv2_snap.dd of=/dev/vg1/lv2_snap

然后我尝试安装lv2_snap，我得到了

can't ready superblock. 
sudo mount /dev/vg1/lv2_snap snap_recover/
mount: /home/wxue/snap_recover: can't read superblock on /dev/mapper/vg1-lv2_snap

。

尝试从备份中恢复超级块不起作用：

sudo mke2fs -n /dev/vg1/lv2_snap
mke2fs 1.44.6 (5-Mar-2019)
Creating filesystem with 512000 1k blocks and 128016 inodes
Filesystem UUID: 5078cdaa-b0fc-42ca-a173-94c4dcc0a739
Superblock backups stored on blocks:
        8193, 24577, 40961, 57345, 73729, 204801, 221185, 401409

sudo e2fsck -b 8193 /dev/vg1/lv2_snap
e2fsck 1.44.6 (5-Mar-2019)
e2fsck: Invalid argument while trying to open /dev/vg1/lv2_snap

如何从 dd 文件恢复？

添加 lvm 版本：

$sudo lvm version
  LVM version:     2.02.176(2) (2017-11-03)
  Library version: 1.02.145 (2017-11-03)
  Driver version:  4.39.0
  Configuration:   ./configure --build=x86_64-linux-gnu --prefix=/usr --includedir=${prefix}/include --mandir=${prefix}/share/man --infodir=${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --disable-silent-rules --libdir=${prefix}/lib/x86_64-linux-gnu --libexecdir=${prefix}/lib/x86_64-linux-gnu --runstatedir=/run --disable-maintainer-mode --disable-dependency-tracking --exec-prefix= --bindir=/bin --libdir=/lib/x86_64-linux-gnu --sbindir=/sbin --with-usrlibdir=/usr/lib/x86_64-linux-gnu --with-optimisation=-O2 --with-cache=internal --with-clvmd=corosync --with-cluster=internal --with-device-uid=0 --with-device-gid=6 --with-device-mode=0660 --with-default-pid-dir=/run --with-default-run-dir=/run/lvm --with-default-locking-dir=/run/lock/lvm --with-thin=internal --with-thin-check=/usr/sbin/thin_check --with-thin-dump=/usr/sbin/thin_dump --with-thin-repair=/usr/sbin/thin_repair --enable-applib --enable-blkid_wiping --enable-cmdlib --enable-cmirrord --enable-dmeventd --enable-dbus-service --enable-lvmetad --enable-lvmlockd-dlm --enable-lvmlockd-sanlock --enable-lvmpolld --enable-notify-dbus --enable-pkgconfig --enable-readline --enable-udev_rules --enable-udev_sync

$uname -a
Linux WVM 5.0.0-21-generic #22-Ubuntu SMP Tue Jul 2 13:27:33 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

答案1

关于逻辑卷的更多信息，我尝试使用精简池和缓存

sudo lvs
  LV        VG  Attr       LSize   Pool      Origin Data%  Meta%  Move Log Cpy%Sync Convert
  cache     vg1 Cwi---C--- 100.00m
  cache1    vg1 Cwi---C--- 100.00m
  lv2       vg1 owi-aotz-- 500.00m thin-pool        4.97
  lv2_snap   vg1 swi-I-s--- 100.00m           lv2    100.00
  lv3       vg1 Vwi-a-tz-- 500.00m thin-pool        0.00
  lv4       vg1 -wi-a----- 500.00m
  lvol0     vg1 -wi-a-----   4.00m
  lvol2     vg1 Cwi---C--- 100.00m
  thin-pool vg1 twi-aotz-- 500.00m                  4.97   11.23

lv 转换也失败，如下所示：

sudo lvconvert --merge /dev/vg1/lv2_snap
  Unable to merge invalidated snapshot LV "lv2_snap".

这是我发现的，我无法恢复到快照逻辑卷，我必须创建一个新的逻辑卷，然后恢复它。

sudo lvcreate -L 500M -n lv5 vg1
  WARNING: Sum of all thin volume sizes (1000.00 MiB) exceeds the size of thin pools (no free space in volume group).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Logical volume "lv5" created.

$sudo dd if=lv2snap.dd of=/dev/vg1/lv5
sudo mount /dev/1024000+0 records in
1024000+0 records out
524288000 bytes (524 MB, 500 MiB) copied, 17.9297 s, 29.2 MB/s

$sudo mount /dev/vg1/lv5 snap_recover/

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