Sabayon Linux 4 is one of a handful of Linux distro that uses LVM as the default disk partitioning scheme. Linux Logical Volume Manager (LVM) is a feature built into the Linux kernel that brings some benefits to hard disk configuration and management under Linux that is not possible with the traditional method of disk management. It makes it possible to, for example, dynamically resize a logical volume (partition) on a running system.
If you are new to Linux, and to the concept of logical volume management, we recommend that you read the basic benefits of using LVM, and how Linux distros configure and manage LVM.
By default, the Sabayon installer creates two logical volumes – one for swap and the other for the root (/) partition. This approach is not necessarily the best way of setting up LVM. In this tutorial, we give step-by-step instructions on how to create a custom LVM setup on Sabayon Linux 4.
Before delving into the tutorial, we should point out that on Sabayon, it is not yet possible to create encrypted LVM volumes. If that is important to you, you should consider Debian, Fedora, or Mandriva.
Setting up LVM involves the following steps:
- Create a non-LVM partition for /boot
- Create a Physical Volume
- Create a Volume Group and assign the Physical Volume to the Volume Group
- Finally, create Logical Volumes
For this tutorial, we intend to create separate logical volumes for / (the root directory), /usr, /var, /tmp, /home, /opt, /usr/local, and swap. To reduce the number of screenshots, we begin this tutorial at the point in the installation process where the installer presents the hard disk(s) detected on the PC, and end it after all the logical volumes have created. For a complete step-by-step installation guide – with screenshots, read the Sabayon Linux 4 installation guide
Now, on to the tutorial.
When configuring LVM, the first partition you create must be a non-LVM partition for /boot. The boot directory, /boot, is where all the static files required to boot the system are stored. Most distros typically assign about 100 MB to /boot, and this should be more than enough. The installer should set it up as a primary partition, but just to be sure, make sure that Force to be a primary partition is checked.
With /boot out of the way, now is the time to create a Physical Volume (PV). Creating a PV initializes the rest of the space for use by LVM. To do this, select the free space, then click on the New button.
The only options you need to change to create a PV is to set the File System Type to physical volume (LVM), and make sure, if you intend to use all the available free space for LVM, that the radio button next to Fill to maximum allowable size is on. Click OK. If you were doing this from the command line, this is where the pvcreate command would have been used.
Now that a PV has been created, the next step is to create a Volume Group (VG), assign the PV to the VG, and then create logical volumes from the available space on the VG. In LVM parlance, a logical volume (LV) is the equivalent of a partition, and a VG is just a virtual container of LVs and PVs. To perform the aforementioned tasks, select the PV (/dev/sda2 on the screenshot) you just created and click on the LVM button.
The first thing we need to do is name the VG. By default, the name of the VG is VolGroup00, but you can give it any name you feel comfortable with. Because only one PV has been created, notice that is automatically selected under Physical Volumes to use. With the VG named, and the PV assigned to the VG, click on the Add button to the lower right side of the window to start creating LVs.