logical volume

Logical volume management is a disk abstraction layer that allows you to group physical disks into a single entity called a volume group.

The inter-disk policy defines the number of disks on which the physical partitions of a logical volume actually resides.

Logical volume management (LVM) is a way systems can abstract physical volume management into a higher-level and usually simpler paradigm.

A machine running AFS File Server needs to have at least one partition or logical volume for storing AFS Volumes.

Every filesystem in Solaris corresponds to a slice or to a logical volume (if you are using Veritas).

Layer the Logical Volume Manager (LVM) between the disk and the file system. Doing so allows you to extend the EBS volume at a later time.

So after the assignment of PVs to the volume group, you can create a logical volume of any size (to the maximum of the VG size).

Now that I had my volume group, I was ready to create a logical volume.

Each logical volume is associated with a volume group, and each volume group typically contains several logical volumes.

The logical volume is like a block device for all purposes, including but not limited to using it as a raw partition for databases.

The logical volume name should also be based upon the previously defined resource group name.

This section defines the Logical Volume Manager (LVM) and introduces some of its features.

Resizing the logical volume itself is accomplished by means of the lvresize command.

Then add a four-character alphanumeric identifier that uniquely identifies the logical volume followed by the characters lv.

Conceptually, the logical volume layer sits between the application and physical layers.

Using logical volume management lets you quickly add more disk capacity to your system without having to shuffle your data around.

This view provides a detailed description of your logical volume attributes.

Before the Logical Volume Manager can be configured, the current partitioning scheme has to be written to disk.

The BLKGETSIZE64 ioctl is being added to all the devices in Linux, and in this case, the logical volume manager does not support it yet.

We still have the original logical volume residing in rootvg, with no mount point associated with it.

It reports on all layers of file system utilization, including the Logical Volume Manager (LVM), virtual memory, and physical disk layers.

This includes the physical architecture, logical disk geometry, and logical volume and file system configuration.

From the previous output, we see that the destination logical volume is set to jfs2.

This was half the size of the original (source) logical volume.

One the logical volume has been expanded, you can then expand your ext2 or ReiserFS filesystem to take advantage of this new space.

The first is an external snapshot which uses a separate logical volume for the snapshot image.

No logical volume-based or file system backing devices should be exported to the client partition.

The System Administration Manager(SAM) hangs when I select a logical volume option.

If you want to shrink a logical volume, the task is a bit more complex.

The -l flag of lslv lists all the physical volumes associated with the logical volumes and distribution for each logical volume.

To resize a logical volume, you click its name in the left panel, then click the Edit Properties button that appears in the middle panel.

Also try not to allocate more than one paging logical volume for each physical disk.

You can then determine that 100 percent of the physical partitions on the disk are allocated to this logical volume.

This command adjusts the size of the specified logical volume.

Due to kernel limitations, the extent size determines the maximum size that a logical volume can be.

A rectangle running across the three disks shows a logical volume (LV) placed across the three disks.

An LVM configuration makes it possible to combine disk space from several small disks into one big logical volume.

Logical Volume Management (LVM) is new to RHEL 3 and is more important than the prerequisite skills covered in most of this chapter.

After the operation, the snapshot is removed (including the associated logical volume).

Finally, the chain of logical volume names is then stored in a chain database.

Afterwards, also extend the filesystem inside the logical volume (they are two separate things, remember).

Logical volume will be defined per volume group on one log; however, multiples might be defined.

One of the most important services available in Linux is the Logical Volume Manager (LVM).

The logical volume and file system characteristics are also inherited.

This can make it very convenient when monitoring specific applications and correlating that with the specific logical volume usage.

You are not actually destroying anything, rather you are formatting a newly created logical volume.

The logical volume copy is now complete.

With the copy command, parse it to the new logical volume, pluto_lv.

This section goes over using a specific logical volume tuning command.

Each logical partition in the logical volume now has at most two physical partitions.

A chain of logical volume names that belongs to the multi-volume dataset is then built.

You can also create logical volume management (LVM) and RAID configurations much as you would on MBR disks.

Finally, we use mkreiserfs to create a filesystem on top of our new logical volume.

There's also an interesting HOWTO that shows you how to set up your root filesystem on a logical volume.

Create the virtual target device that maps the virtual SCSI device to the logical volume (see Listing 6).

The bootstrap then loads the Boot Logical Volume (BLV) into memory.

The next task is to initialize and format the logical volume jfs2log_lv so it can be used as a jfs2 log.

How do I remove a copy of a logical volume?

the new memory space is named as the logical volume.

Next, you'll see the tools needed for filesystem and Logical Volume Management (LVM).

For example, while a physical disk cannot be resized, a logical volume can be resized to add or remove space from it.

Create a logical volume for the original image.

Figure 14 shows the logical volume, physical volume, file system, and volume group.

That is, the size of the file system contained in the logical volume is not altered.

You would do this with the reorgvg command, which can improve logical volume utilization and efficiency.

Create a volume group and logical volume to hold the client's rootvg.

To create an LVM logical volume, we follow a three-step process.

And the logical volume should be renamed to pluto_lv.

I specified a size of 128MB for the snapshot logical volume (LV).

No free volume groups were found for creating a new logical volume.

Mail journaling was set up on a separate logical volume.

In Figure 5, you'll input the name of the logical volume, oralv, and request a size of 4. 9 GB.

You can transparently encrypt a block device or a logical volume with dm_crypt.

These attributes reflect the log and device when the logical volume resided in rootvg.

The basis for all file system discussion is a logical volume of some sort.

When you do a basic AIX install, the default paging space is a logical volume called hd6.

When you are done with creating all your partitions, you should start the logical volume manager as usual.

The paging space itself is a special logical volume that stores the information that is currently not accessed.

JFS and JFS2 file systems require a logical volume for the JFS log.

This is a simple task because we used logical volume management.

The bosboot command is run to create a client boot image, which is written to the client's alternate boot logical volume (alt_hd5).

Figure 12 shows an example disk layout using logical volume management.

In this series, I'm going to show you how to install and use the new Logical Volume Management support built-in to the Linux 2. 4 kernel.

This is very helpful when drilling down to the logical volume layer when tuning your systems.

So the first task is to unmount the filesystem we wish to copy, so that we can access the logical volume.

You must also offer a path to the logical volume.

the logical volume manager writes the date to be changed in the logic volume into the new memory space;

Strategy of Disaster Recovery of Remote Logical Volume Replication System on Linux

Finally, with the logical volume ready, format it with whatever filesystem you prefer and then mount it under the desired mount point

Copying a logical volume to a different volume group

Add a Journaled File System on a Previously Defined Logical Volume

Next, increase the logical volume within this volume group. You can verify with lvdisplay by comparing the LV Size row

Let's look at how to copy a logical volume to a different volume group. The steps involved are

Design of virtual network storage based on logical volume manager

Run the following command to display information about the logical volume lv1

View and edit logical volume

You can remove the logical volume lv7 by running the following command

To increase the size of the logical volume represented by the lv05 directory by three logical partitions, for example, type

Increased maximum logical volume size: 2 - 16TB

Now that it is set to copy, we can copy the logical volume