Red Hat Enterprise Virtualization 3.1 offers new storage features, including storage live migration and Red Hat Storage. In addition to storage improvements, both features
Managing multiple data centers with ease
One of the basic building blocks of a Red Hat Enterprise Virtualization (RHEV) environment is the data center. Every virtual machine (VM) is built on a specific data center. The data center in RHEV doesn't mirror a physical data center where you install servers, but it's the basic entity in a RHEV configuration. Every RHEV environment has at least one data center with the name Default, but you can have more than one data center in a RHEV domain.
Each data center is configured to use a specific kind of storage. After selecting a specific kind of storage for your data center, you won't be able to change the storage type or add a new storage type. This would come in handy if, for example, more than one storage technology is used in a physical data center.
Larger virtual environments often employ more than one storage area network (SAN). A company might, for instance, have one iSCSI SAN and one Fibre Channel SAN. For a versatile RHEV-based architecture, you might want to integrate both of these SAN technologies. To accomplish that, you would need to add an additional data center and assign VMs to it.
When working with different data centers in one environment, the ability to migrate VMs from one to another comes in handy. In previous versions of RHEV, you could only migrate VMs after shutting them down. Depending on the workload, the downtime required to migrate VMs could mean lost revenue. Now, with RHEV 3.1, you can simply live-migrate a VM from one data center to another without downtime.
To perform storage live migration, the disk used by a VM is synchronized from one SAN to another while the VM continues to run. You can also use this technique in large cloud environments if you need to load balance VMs between different clouds.
File distribution with Red Hat Storage
Further reading on RHEV 3.1 features
The new RHEV 3.1 management interface
RHEV 3.1 competes with vSphere and Hyper-V
Red Hat Storage is a new distributed file system based on the Gluster file system. In Red Hat Storage, files are stored in different physical locations, but are presented as one file system structure that is completely unaware of the underlying storage location. Within the feature, you can configure storage in different ways, with built-in redundancy as well. Red Hat Storage allows you to make storage available where needed, while still presenting it as one entity in which the dispersion is not visible and without reconfiguring the storage layer. These abilities would also be useful for Platform as a Service providers.
When compared with the new features introduced in RHEV 3.0, storage live migration and the integration of Red Hat Storage may seem insignificant. Both features, however, increase RHEV's flexibility, especially in cloud environments. Red Hat has effectively solidified its cloud provisioning strategy with the addition of these new storage features.
This was first published in April 2013