Local storage consists of hard disks installed locally in your Oracle VM Server. For SPARC, this includes SAS disks and ZFS volumes . In a default installation, Oracle VM Server detects any unused space on the installation disk and repartitions the disk to make this space available for local storage. As long as no partition and data are present, the device is detected as a raw disk. The choice is yours to use the local disks, either to provision logical storage volumes as disks for virtual machines, or to install a storage repository. See Creating ZFS Volumes on SPARC in the Oracle VM Administrator's Guide for more information on setting up ZFS volumes for Oracle VM Server for SPARC. Also note that SAS disk support is limited to the SAS controller using the mpt_sas driver. This means that there is internal SAS disk support on T3 and later, but internal SAS disks on T2 and T2+ are unsupported.

If you place a storage repository on a local disk in an x86 environment, an OCFS2 file system is created. If you intend to create a storage repository on a local disk, the disk must not contain any data or meta-data. If it does, it is necessary to clean the disk manually before attempting to create a storage repository on it. This can be done using the dd command, for example:

# dd if=/dev/zero of=/dev/disk bs=1M

Where disk is the device name of the disk where you want to create the repository.

In SPARC environments, a storage repository is created using the ZFS file system. If you use a local physical disk for your storage repository, a ZFS pool and file system are automatically created when you create the repository. If you use a ZFS volume to host the repository, the volume is replaced by a ZFS file system and the repository is created within the file system.

Local storage can never be used for a server pool file system.

Local storage is fairly easy to set up because no special hardware for the disk subsystem is required. Since the virtualization overhead in this set up is limited, and disk access is internal within one physical server, local storage offers reasonably high performance.

While local storage has the advantage that it is fast and easy to use, there is no possibility to share this type of storage and it cannot be used in a high-availability configuration. Consequently, if you need to store important data and run important virtual machines that require virtually uninterrupted uptime with a high degree of data loss prevention, it is recommended not to use local storage, but to invest in attached storage with proper redundancy instead.

In addition, local storage lacks flexibility in a clustered set up with multiple Oracle VM Servers in a server pool. Resources and virtual disks that live on local storage cannot be shared with other Oracle VM Servers, even if they are within the same server pool. This means that you cannot use a template, ISO, or virtual disk stored on a local repository on another Oracle VM Server, and that live migration of virtual machines with locally stored disks is impossible. We strongly advise you to take this into account when designing your Oracle VM environment.

The configuration where local storage is most useful is where you have an unclustered server pool that contains only one Oracle VM Server. By creating a storage repository (see Section 4.3, “How is a Repository Created?”) on local storage you can set up an Oracle VM virtualized environment quickly and easily on a single Oracle VM Server: all your resources, virtual machines and their disks are stored locally. Since there is only one Oracle VM Server, access to resources is guaranteed.