2.2.4.2 LVM

Because I am using two 250GB drives, I need to use LVM to make them look like one large disk.  In addition I want to be able to add more drives without having to upgrade to a larger drive.  If I use LVM I will be able to add another drive and then add it to the Volume Group and extend the MythTV Storage Logical Drive.

Install LVM

The LVM doesn't come with the Ubuntu Desktop.  After you install the LVM you need to reboot to install the kernel modules.
 

sudo apt-get install lvm2
sudo shutdown -r now

Patition the disks

Create partitions on disks, make sure to mark the paritions as 0x8e (Linux LVM).  It is best to create a partition even if you are using the whole disk.


Add the paritions to LVM
 

$ sudo pvcreate /dev/sdb1 /dev/sdc1
  Physical volume "/dev/sdb1" successfully created
  Physical volume "/dev/sdc1" successfully created

Create Volume Group
 

$ sudo vgcreate mythtv_storage /dev/sdb1 /dev/sdc1
  Volume group "mythtv_storage" successfully created

Create a Logical Volume

Because I want to create a logical volume the total size of the two disks I will first get the "Total PE" from volume group.
 

$ sudo vgdisplay mythtv_storage
  --- Volume group ---
  VG Name               mythtv_storage
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               465.71 GB
  PE Size               4.00 MB
  Total PE              119222
  Alloc PE / Size       0 / 0
  Free  PE / Size       119222 / 465.71 GB
  VG UUID               02bG3B-Ua9y-zQEK-JmfF-yIq5-lLmE-OcZCMK

$ sudo lvcreate -l 119222 mythtv_storage -n mythtvlv

Create File System
 

sudo mke2fs /dev/mythtv_storage/mythtvlv
mke2fs 1.40.2 (12-Jul-2007)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
61046784 inodes, 122083328 blocks
6104166 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
3726 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
        102400000

Writing inode tables: done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 39 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

Mount filesystem


Resources

    Linux LVM HowTo -- http://tldp.org/HOWTO/LVM-HOWTO/index.html