- Why convert to EVMS?
Everyone who has installed Linux is probably familiar with partitioning
hard-drives, usually with a program like fdisk, cfdisk or Disk-Druid. Many
people have also added software-RAID to their system using tools like mdadm
or raidtools. Others use LVM tools as well to create volume groups and
logical volumes. Finally, those partitions and volumes need filesystems on
top of them in order to be useful, and there are four commonly used filesystems
to choose from.
This is a lot of different tools to learn just for managing your storage
devices. Each tool has a different interface - some are purely command-line,
some have interactive shells, some have ncurses-based UIs. Some tools have
extra configuration files and all the tools have different options. In
addition, using a combination of these tools may involve subtle ordering
issues when it comes to booting your system or making changes to one aspect
of your storage.
The Enterprise Volume Management System (EVMS) allows you to do away with all
of these different tools. It provides all your storage management needs in one
easy-to-use interface. It automatically handles all of the ordering issues
associated with getting your partitions and volumes running at boot-time, and
with making configuration changes on your running system.
If you're looking to for an easier solution for storage administration, we
highly recommend converting to EVMS.
- Download the EVMS packages.
The first step in converting to EVMS is to obtain all of the necessary
packages. Please see the
section of the installation instructions for a list of all packages that are
required for building and running EVMS.
- Compile the kernel.
The next step is to patch, configure, and compile your kernel to support
EVMS. The kernel
section of the installation instructions will give you all the details about
which patches to apply and which options to choose.
If you are currently using LVM1, be sure to leave that option enabled in
your kernel configuration, since you'll be booting this new kernel before
you've fully converted to EVMS. The LVM1 and Device-Mapper drivers can
co-exist in the same kernel without problems. After the conversion to EVMS is
complete, you may go back and recompile your kernel again without LVM1 support.
EVMS also uses the MD driver for performing software-RAID. If you are currently
using raidtools or mdadm for software-RAID, you should simply keep the same
kernel RAID options that you already have enabled.
After compiling, reboot your machine using the new kernel.
- Compile the EVMS tools.
After rebooting, the next step is to build and install EVMS. See the
tools section of
the installation instructions for details.
- Run the EVMS UI.
Since you've already booted your Device-Mapper-enabled kernel, you can
immediately start one of the EVMS user-interfaces. If you're running a
graphical desktop, run evmsgui. If you're using a text terminal,
run evmsn. The first screen you will see with either of these UIs
is the Volumes panel. Explore all the panels in the UI to see how EVMS
represents the various devices and volumes on your system.
The most important thing to notice right now is the names that EVMS assigns to
your existing volumes. Because your existing volumes are discovered as
compatibility volumes, the names will be similar to what you've previously been
using. All volume names begin with /dev/evms. Here are a few specific
- A simple disk partition called /dev/hda5 will appear in EVMS as
- A software-RAID device called /dev/md1 will appear in EVMS as
- An LVM1 volume called /dev/my_group/my_volume will appear in EVMS
- Update /etc/fstab to use EVMS volume names.
To use your EVMS volumes, you must tell Linux to mount them instead of your
existing partitions and volumes. The best way to do this is to edit your
/etc/fstab file and change the device name for each entry to the
corresponding EVMS volume names. For example, the following entry for an LVM
/dev/my_group/home_volume /home reiserfs defaults 1 2
would change to:
/dev/evms/lvm/my_group/home_volume /home reiserfs defaults 1 2
With these changes, each time your system boots, your filesystems will be
mounted using the EVMS volumes.
- Update the boot-scripts.
As explained in the
section of the installation instructions, the command evms_activate
must be run from your boot-scripts in order to activate your volumes so they
can be mounted. In addition to this change, if you run software-RAID or LVM1
tools (e.g. raidstart, vgscan, or vgchange) during
your boot-scripts, those commands should be removed or disabled.
- Update the bootloader.
In order to mount your root filesystem using EVMS, you must install the EVMS
init-ramdisk image and update your boot-loader configuration. Please see the
sections of the installation instructions for the complete details.
- One more reboot.
Now that all of these items have been configured, you just need to reboot your
machine one more time. When it boots, the kernel will load the init-ramdisk,
which will run the EVMS tools to activate your volumes and mount your root
filesystem. Then your boot-scripts will run the EVMS tools once more to make
sure your /dev/evms/ directory correctly reflects the current state of
your volumes. Finally, the remaining EVMS volumes will be mounted as specified
in your /etc/fstab file. Everything else on your system should start
up as you would normally expect.