Mike Chirico (mchirico@users.sourceforge.net) or (mchirico@comcast.net)
Copyright (C) 2006 (GNU Free Documentation License)
Last Updated: Wed Jul 5 10:43:47 EDT 2006
[http://souptonuts.sourceforge.net/lvm_tutorial.html]

LVM Tutorial - AoE, Fuse, and loopback devices.

LVM (Linux Volume Management) tutorial using Aoe, Fuse and loopback devices with different RAID levels 1,5, and 10.

Structure to follow:

AoE

The first step is to install the kernel source. 

     yum install kernel-devel

      This picked  kernel-devel-2.6.1

It's possible this is already installed. 

     yum list|grep 'kernel-devel*'
kernel-devel.i686                        2.6.17-1.2157_FC5      installed
kernel-devel.i586                        2.6.17-1.2157_FC5      updates

Next download aoe tools and vblade, and create the necessary directories. I use the following script. 

     mkdir -p /home/src/aoe
     cd /home/src/aoe
     wget http://www.coraid.com/support/linux/aoe6-31.tar.gz
     tar -xzf aoe6-31.tar.gz

     mkdir -p /home/src/vblade
     cd /home/src/vblade

     wget http://ftp1.sourceforge.net/aoetools/vblade-10.tar.gz
     tar -xzf vblade-10.tar.gz

Next compile the software. 

      cd /home/src/aoe/aoe6-31
      make install
      modproble aoe

      cd /home/src/vblade/vblade-10
      make

Now create the disk images. See (diskcreate.sh). 

     dd if=/dev/zero of=/images/disk0.img count=102400
     dd if=/dev/zero of=/images/disk1.img count=102400
     dd if=/dev/zero of=/images/disk2.img count=102400
     dd if=/dev/zero of=/images/disk3.img count=102400

Next map the loopback device 

     losetup `losetup -f` /images/disk0.img
     losetup `losetup -f` /images/disk1.img
     losetup `losetup -f` /images/disk2.img

Take a look at what is being used. 

      fdisk -l
      cat /proc/mdstat

Create the raid. Note it is also possible to create the raid on a remote device too; but, vbladed would need to be run first. (Note to self: Document this later as well). 

     mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/loop0 /dev/loop1 /dev/loop2

Now take a look at the status. 

    cat /proc/mdstat
Personalities : [raid5] [raid4]
md0 : active raid5 loop2[2] loop1[1] loop0[0]
      102272 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

unused devices: none

Also, you can get more information with the following: 

      mdadm --detail /dev/md0

Now, we'll run vbladed on living room. 

    cd /home/src/vblade/vblade-10
    ./vbladed 12 0 eth0 /dev/md0

Take a look at the log files. 

Jul 27 12:42:24 livingroom vbladed: ioctl returned 0
Jul 27 12:42:24 livingroom vbladed: 104726528 bytes
Jul 27 12:42:24 livingroom vbladed: pid 2144: e12.0, 204544 sectors

Now log in to another computer on the same subnet, which has the aoe tools installed and compiled. Note, to compile you'll need the kernel source. 

     ssh v5
     yum install kernel-xenU-devel   #This Xen domain
# There is also yum install kernel-xen0-devel
     cd /home/src/aoe/aoe6-31
     make install
     modprobe aoe
     lsmod|grep 'aoe'
aoe       33920  0

     aoe-stat
e12.0         0.104GB   eth0 up

Remember, the commands above were executed on the remote computer. Continuting on the remote computer.

Next, run pvcreate 

     pvcreate /dev/etherd/e12.0
     vgcreate AoEVolGroup00 /dev/etherd/e12.0
Volume group "AoEVolGroup00" successfully created

     lvcreate -L51 -n lpLogVol00 AoEVolGroup00 

If you need to remove: lvremove -f AoEVolGroup00/lpLogVol00

Rounding up size to full physical extent 52.00 MB
Logical volume "AoEVolGroup00" created

     ls /dev/AoEVolGroup00/
lpLogVol00

The lvcreate command only uses 51 MB. It can be extended later. Next format this volume. 

     mkfs -t ext3 /dev/AoEVolGroup00/lpLogVol00
or
     yum install reiserfs-utils
     mkfs -t reiserfs /dev/AoEVolGroup00/lpLogVol00
of
     yum install xfsprogs*
     mkfs.xfs  -f /dev/AoEVolGroup00/lpLogVol00

  
     mkdir -p /AoE
     mount /dev/AoEVolGroup00/lpLogVol00  /AoE

  to unmount

     umount /AoE

Now run vgscan. 

     vgscan
     vgchange -ay lp_volumes  #Make this active


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Chirico img Mike Chirico, a father of triplets (all girls) lives outside of Philadelphia, PA, USA. He has worked with Linux since 1996, has a Masters in Computer Science and Mathematics from Villanova University, and has worked in computer-related jobs from Wall Street to the University of Pennsylvania. His hero is Paul Erdos, a brilliant number theorist who was known for his open collaboration with others.


Mike's notes page is souptonuts. For open source consulting needs, please send an email to mchirico@comcast.net. All consulting work must include a donation to SourceForge.net.
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