JFIF$        dd7 

Viewing File: /usr/lib/dracut/modules.d/80lvmmerge/README.md

# lvmmerge - dracut module

## Preparation
- ensure that the lvm thin pool is big enough
- backup any (most likely /boot and /boot/efi) device with:
```
# mkdir /restoredev
# dev=<device>; umount $dev; dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev"); mount $dev
```
- backup the MBR
```
# dev=<device>; dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev") bs=446 count=1
# ls -l /dev/disk/by-path/virtio-pci-0000\:00\:07.0
lrwxrwxrwx. 1 root root 9 Jul 24 04:27 /dev/disk/by-path/virtio-pci-0000:00:07.0 -> ../../vda
```
- backup some partitions
```
# dev=/dev/disk/by-path/virtio-pci-0000:00:07.0
# dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev") bs=446 count=1
# umount /boot/efi
# dev=/dev/disk/by-partuuid/687177a8-86b3-4e37-a328-91d20db9563c
# dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev")
# umount /boot
# dev=/dev/disk/by-partuuid/4fdf99e9-4f28-4207-a26f-c76546824eaf
# dd if="$dev" of=/restoredev/$(systemd-escape -p "$dev")
```
Final /restoredev
```
# ls -al /restoredev/
total 1253380
drwx------.  2 root root        250 Jul 24 04:38 .
dr-xr-xr-x. 18 root root        242 Jul 24 04:32 ..
-rw-------. 1 root root  209715200 Jul 24 04:34 dev-disk-by\x2dpartuuid-4fdf99e9\x2d4f28\x2d4207\x2da26f\x2dc76546824eaf
-rw-------. 1 root root 1073741824 Jul 24 04:34 dev-disk-by\x2dpartuuid-687177a8\x2d86b3\x2d4e37\x2da328\x2d91d20db9563c
-rw-------. 1 root root        446 Jul 24 04:38 dev-disk-by\x2dpath-virtio\x2dpci\x2d0000:00:07.0
```
- make a thin snapshot
```
# lvm lvcreate -pr -s rhel/root --name reset
```

- mark the snapshot with a tag
```
# lvm lvchange --addtag reset rhel/reset
```

- remove /restoredev
```
# rm -fr /restoredev
```

## Operation

If a boot entry with ```rd.lvm.mergetags=<tag>``` is selected and there are LVs with ```<tag>```
dracut will
- make a copy of the snapshot
- merge it back to the original
- rename the copy back to the name of the snapshot
- if /restordev appears in the root, then it will restore the images
  found in that directory. This can be used to restore /boot and /boot/efi and the
  MBR of the boot device
Back to Directory  nL+D550H?Mx ,D"v]qv;6*Zqn)ZP0!1 A "#a$2Qr D8 a Ri[f\mIykIw0cuFcRı?lO7к_f˓[C$殷WF<_W ԣsKcëIzyQy/_LKℂ;C",pFA:/]=H  ~,ls/9ć:[=/#f;)x{ٛEQ )~ =𘙲r*2~ a _V=' kumFD}KYYC)({ *g&f`툪ry`=^cJ.I](*`wq1dđ#̩͑0;H]u搂@:~וKL Nsh}OIR*8:2 !lDJVo(3=M(zȰ+i*NAr6KnSl)!JJӁ* %݉?|D}d5:eP0R;{$X'xF@.ÊB {,WJuQɲRI;9QE琯62fT.DUJ;*cP A\ILNj!J۱+O\͔]ޒS߼Jȧc%ANolՎprULZԛerE2=XDXgVQeӓk yP7U*omQIs,K`)6\G3t?pgjrmۛجwluGtfh9uyP0D;Uڽ"OXlif$)&|ML0Zrm1[HXPlPR0'G=i2N+0e2]]9VTPO׮7h(F*癈'=QVZDF,d߬~TX G[`le69CR(!S2!P <0x<!1AQ "Raq02Br#SCTb ?Ζ"]mH5WR7k.ۛ!}Q~+yԏz|@T20S~Kek *zFf^2X*(@8r?CIuI|֓>^ExLgNUY+{.RѪ τV׸YTD I62'8Y27'\TP.6d&˦@Vqi|8-OΕ]ʔ U=TL8=;6c| !qfF3aů&~$l}'NWUs$Uk^SV:U# 6w++s&r+nڐ{@29 gL u"TÙM=6(^"7r}=6YݾlCuhquympǦ GjhsǜNlɻ}o7#S6aw4!OSrD57%|?x>L |/nD6?/8w#[)L7+6〼T ATg!%5MmZ/c-{1_Je"|^$'O&ޱմTrb$w)R$& N1EtdU3Uȉ1pM"N*(DNyd96.(jQ)X 5cQɎMyW?Q*!R>6=7)Xj5`J]e8%t!+'!1Q5 !1 AQaqё#2"0BRb?Gt^## .llQT $v,,m㵜5ubV =sY+@d{N! dnO<.-B;_wJt6;QJd.Qc%p{ 1,sNDdFHI0ГoXшe黅XۢF:)[FGXƹ/w_cMeD,ʡcc.WDtA$j@:) -# u c1<@ۗ9F)KJ-hpP]_x[qBlbpʖw q"LFGdƶ*s+ډ_Zc"?%t[IP 6J]#=ɺVvvCGsGh1 >)6|ey?Lӣm,4GWUi`]uJVoVDG< SB6ϏQ@ TiUlyOU0kfV~~}SZ@*WUUi##; s/[=!7}"WN]'(L! ~y5g9T̅JkbM' +s:S +B)v@Mj e Cf jE 0Y\QnzG1д~Wo{T9?`Rmyhsy3!HAD]mc1~2LSu7xT;j$`}4->L#vzŏILS ֭T{rjGKC;bpU=-`BsK.SFw4Mq]ZdHS0)tLg