Because I have received many inquiries about LVM I decided to do a paragraph on this subject more interesting.
First of all, try to give a brief expliación that is a logical volume.
LVM is an implementation of a logical volume manager for the Linux kernel. Was originally written in 1998 by Heinz Mauelshagen, which was based on the Veritas volume manager used in HP-UX systems.
LVM includes many of the features expected of a volume manager, including:
* Resize logical groups
* Resizing logical volumes
* read-only snapshots (LVM2 provides read and write)
* Logical Volume RAID0
Features
* The logical volume management provides a high level view on a computer storage instead of the traditional view of disks and partitions.
* Storage volumes under the control of LVM can be resized and moved at will, although this may need to update your system tools.
* LVM also allows management to user-defined groups, allowing the system administrator to deal with volumes called, for example, "sales" or "development", rather than physical device names such as "sda" or "sdb"
* LVM is widely used in Unix systems as AIX, HP-UX or Solaris , allowing the resizing of volumes, physical space allocated to different volumes, regardless of FileSystem, etc..
While such implementations are always made in large systems that require a dedicated management and 24x7 services to be provided, it is interesting to make a similar home, taking into account all the benefits discussed above
LVM consists of three parts The first is the Volume Group which his name is randomly assigned (Purchases, Sales, IT, etc) and is responsible for being the "container" of the other components of the architecture. Physical Volume
The device name is assigned to the physical device (/ dev/hda1). The Logical Volume
(LV) is the "device" logical to be constituted by parts of the physical volumes.
In the graph below you can see how the whole architecture is
VG (Volume Group)
PV (Physical Volume)
LV (Logical Volume)
As can be seen in the example of PV3 clearly independent of the physical volume, using this technology, you can assign parts of a PV to any LV, resize and reallocate according to needs.
This chart we can see how different technologies can be assigned to the different filesystems.
/ opt / media => XFS
/ mnt / backup => Reiserfs
/ home / share => Reiserfs
here's how to create a logical volume. It should be noted that such instructions have been tested on a RHEL 5.2 and Ubuntu 8.04, and for other distributions, check the documentation before starting the process.
1) Initialization of the device
We as physical volume / dev/sda1
# pvcreate / dev/sda1
Physical volume "/ dev/sda1" successfully created
2) Creating the Volume Group assign "Shopping" as a VG name
# vgcreate Shopping / dev/sda1
Volume group "Shopping" successfully created 3) Creating the Logical Volume #
lvcreate-L1G-n lv1 Shopping
lvcreate - doing automatic backup of "Shopping"
lvcreate - logical volume "/ dev/Compras/lv1" successfully created (Where -L1G is assigned to the LV size In this case 1GB. With the option-n assign the name to Logical volume. Finally we pass the name of the Volume Group which will assign the LV).
4) Formatting the Logical Volume
At this point we have created the VG, PV and LV, we now need to format it and assign a
If everything went While we should be able to mount the device as any volume and write about it.FileSystem # mkfs.jfs / dev/compras/lv1
# mount-t jfs / dev/Compras/lv1 / mnt / Data
* History and Brief Introduction taken from Wikipedia
