<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Splitting a volume group</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="LVM HOWTO" HREF="index.html"><LINK REL="UP" TITLE="Recipes" HREF="recipes.html"><LINK REL="PREVIOUS" TITLE="Moving a volume group to another system" HREF="recipemovevgtonewsys.html"><LINK REL="NEXT" TITLE="Converting a root filesystem to LVM 1" HREF="upgraderoottolvm.html"></HEAD ><BODY CLASS="sect1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >LVM HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="recipemovevgtonewsys.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 13. Recipes</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="upgraderoottolvm.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="recipesplitvg" ></A >13.7. Splitting a volume group</H1 ><P > There is a new group of users "design" to add to the system. One way of dealing with this is to create a new volume group to hold their data. There are no new disks but there is plenty of free space on the existing disks that can be reallocated. </P ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1369" ></A >13.7.1. Determine free space</H2 ><P > <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># pvscan </B > <TT CLASS="computeroutput" >pvscan -- reading all physical volumes (this may take a while...) pvscan -- ACTIVE PV "/dev/sda" of VG "dev" [1.95 GB / 0 free] pvscan -- ACTIVE PV "/dev/sdb" of VG "sales" [1.95 GB / 1.27 GB free] pvscan -- ACTIVE PV "/dev/sdc" of VG "ops" [1.95 GB / 564 MB free] pvscan -- ACTIVE PV "/dev/sdd" of VG "dev" [1.95 GB / 0 free] pvscan -- ACTIVE PV "/dev/sde" of VG "ops" [1.95 GB / 1.9 GB free] pvscan -- ACTIVE PV "/dev/sdf" of VG "dev" [1.95 GB / 1.33 GB free] pvscan -- ACTIVE PV "/dev/sdg1" of VG "ops" [996 MB / 432 MB free] pvscan -- ACTIVE PV "/dev/sdg2" of VG "dev" [996 MB / 632 MB free] pvscan -- total: 8 [13.67 GB] / in use: 8 [13.67 GB] / in no VG: 0 [0]</TT > </PRE ></FONT ></TD ></TR ></TABLE > We decide to reallocate /dev/sdg1 and /dev/sdg2 to design so first we have to move the physical extents into the free areas of the other volumes (in this case /dev/sdf for volume group dev and /dev/sde for volume group ops). </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1375" ></A >13.7.2. Move data off the disks to be used</H2 ><P > Some space is still used on the chosen volumes so it is necessary to move that used space off onto some others. </P ><P > Move all the used physical extents from /dev/sdg1 to /dev/sde and from /dev/sdg2 to /dev/sdf <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># pvmove /dev/sdg1 /dev/sde</B > <TT CLASS="computeroutput" >pvmove -- moving physical extents in active volume group "ops" pvmove -- WARNING: moving of active logical volumes may cause data loss!</TT > <TT CLASS="prompt" >pvmove -- do you want to continue? [y/n]</TT > y <TT CLASS="computeroutput" >pvmove -- doing automatic backup of volume group "ops" pvmove -- 141 extents of physical volume "/dev/sdg1" successfully moved</TT > <B CLASS="command" ># pvmove /dev/sdg2 /dev/sdf</B > <TT CLASS="computeroutput" >pvmove -- moving physical extents in active volume group "dev" pvmove -- WARNING: moving of active logical volumes may cause data loss!</TT > <TT CLASS="prompt" >pvmove -- do you want to continue? [y/n]</TT > y <TT CLASS="computeroutput" >pvmove -- doing automatic backup of volume group "dev" pvmove -- 91 extents of physical volume "/dev/sdg2" successfully moved</TT > </PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1388" ></A >13.7.3. Create the new volume group</H2 ><P > Now, split /dev/sdg2 from dev and add it into a new group called "design". it is possible to do this using vgreduce and vgcreate but the vgsplit command combines the two. <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># vgsplit dev design /dev/sdg2</B > <TT CLASS="computeroutput" >vgsplit -- doing automatic backup of volume group "dev" vgsplit -- doing automatic backup of volume group "design" vgsplit -- volume group "dev" successfully split into "dev" and "design"</TT > </PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1394" ></A >13.7.4. Remove remaining volume</H2 ><P > Next, remove /dev/sdg1 from ops and add it into design. <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># vgreduce ops /dev/sdg1</B > <TT CLASS="computeroutput" >vgreduce -- doing automatic backup of volume group "ops" vgreduce -- volume group "ops" successfully reduced by physical volume: vgreduce -- /dev/sdg1</TT > <B CLASS="command" ># vgextend design /dev/sdg1</B > <TT CLASS="computeroutput" >vgextend -- INFO: maximum logical volume size is 255.99 Gigabyte vgextend -- doing automatic backup of volume group "design" vgextend -- volume group "design" successfully extended</TT > </PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1402" ></A >13.7.5. Create new logical volume</H2 ><P > Now create a logical volume. Rather than allocate all of the available space, leave some spare in case it is needed elsewhere. <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># lvcreate -L750M -n users design</B > <TT CLASS="computeroutput" >lvcreate -- rounding up size to physical extent boundary "752 MB" lvcreate -- doing automatic backup of "design" lvcreate -- logical volume "/dev/design/users" successfully created</TT > </PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1408" ></A >13.7.6. Make a file system on the volume</H2 ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># mke2fs /dev/design/users</B > <TT CLASS="computeroutput" >mke2fs 1.18, 11-Nov-1999 for EXT2 FS 0.5b, 95/08/09 Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 96384 inodes, 192512 blocks 9625 blocks (5.00<!-- ) reserved for the super user First data block=0 6 block groups 32768 blocks per group, 32768 fragments per group 16064 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840 Writing inode tables: done Writing superblocks and filesystem accounting information: done</TT > </PRE ></FONT ></TD ></TR ></TABLE ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="AEN1413" ></A >13.7.7. Mount the new volume</H2 ><TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > <B CLASS="command" ># mkdir -p /mnt/design/users mount /dev/design/users /mnt/design/users/</B > </PRE ></FONT ></TD ></TR ></TABLE ><P > It's also a good idea to add an entry for this file system in your /etc/fstab file as follows: <TABLE BORDER="0" BGCOLOR="#E0E0E0" WIDTH="100%" ><TR ><TD ><FONT COLOR="#000000" ><PRE CLASS="screen" > /dev/design/user /mnt/design/users ext2 defaults 1 2 </PRE ></FONT ></TD ></TR ></TABLE > </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="recipemovevgtonewsys.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="upgraderoottolvm.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Moving a volume group to another system</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="recipes.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Converting a root filesystem to LVM 1</TD ></TR ></TABLE ></DIV ></BODY ></HTML >