254 lines
4.1 KiB
HTML
254 lines
4.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Recover physical volume metadata</TITLE
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="LVM HOWTO"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Recipes"
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HREF="recipes.html"><LINK
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REL="PREVIOUS"
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TITLE="Converting a root filesystem to
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LVM 1"
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HREF="upgraderoottolvm.html"><LINK
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REL="NEXT"
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TITLE="Dangerous Operations"
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HREF="dangerousops.html"></HEAD
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>LVM HOWTO</TH
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WIDTH="10%"
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>Prev</A
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>Chapter 13. Recipes</TD
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><H1
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CLASS="sect1"
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><A
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NAME="recovermetadata"
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></A
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>13.9. Recover physical volume metadata</H1
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><P
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> If you get the warning "incorrect metadata area header checksum"
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or something about not being able to find PV with UUID foo,
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you probably toasted the volume group descriptor area and lvm
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startup can't occur.
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</P
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><DIV
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CLASS="warning"
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><P
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></P
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><TABLE
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CLASS="warning"
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WIDTH="100%"
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BORDER="0"
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><TD
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WIDTH="25"
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ALIGN="CENTER"
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SRC="../images/warning.gif"
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HSPACE="5"
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ALT="Warning"></TD
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><TH
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ALIGN="LEFT"
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VALIGN="CENTER"
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><B
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>Only run on non-functional VG</B
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></TH
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></TR
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><TR
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><TD
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> </TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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><P
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> Don't do this on a properly working lvm.
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You need to specify the correct physical volume to
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<B
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CLASS="command"
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>pvcreate</B
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> or you may lose your data.
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</P
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></TD
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></TR
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></TABLE
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></DIV
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><P
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> Extract the exact uuid for the PV that was overwritten from the file
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<TT
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CLASS="filename"
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>/etc/lvm/archive/VolumeGroupName_XXXXX.vg</TT
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>.
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(Where XXXXX represents the number of the last known good archived lvm
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metadata).
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</P
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><P
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> Use <B
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CLASS="command"
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>pvcreate</B
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> to restore the metadata:
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<B
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CLASS="command"
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>pvcreate --uuid "<some_long_string>" --restorefile /etc/lvm/archive/VolumeGroupName_XXXXX.vg <PhysicalVolume></B
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>
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</P
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><P
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> If you are lucky you'll find that the on-disk lvm metadata takes
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at least so much space as what it was overwritten with. The above
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command has been know to recover a PV overwritten with mkswap. If
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whatever overwrote the VGDA writes past that area, LVs may be affected.
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In this case, fsck might be able to fix the filesystem on the LV, or
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you may need more drastic measures to pull data off of it. Contact
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your local friendly filesystem expert for help in that case.
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</P
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><DIV
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CLASS="note"
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><P
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ALIGN="CENTER"
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VALIGN="TOP"
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SRC="../images/note.gif"
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HSPACE="5"
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ALT="Note"></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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><P
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><B
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CLASS="command"
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>pvcreate</B
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> only overwrites the lvm metadata
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areas on disk and doesn't touch the data areas (the logical
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volumes).
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</P
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></TD
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></TABLE
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HREF="upgraderoottolvm.html"
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>Prev</A
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Converting a root filesystem to
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LVM 1</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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>Dangerous Operations</TD
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> |