Managing EVMS Devices

This section describes how to initialize a disk for EVMS management by adding a segment management container to manage the partitions that you later add to the disk.

Understanding Disk Segmentation

In EVMS, you initialize a disk by assigning a segment manager to it. The segment manager creates metadata for the disk and exposes its free space so you can subdivide it into one or multiple segments (also called partitions).

Segment Managers

The most commonly used segment manager is the DOS Segment Manager. The following table describes the segment managers available in EVMS.

Table 4.1. EVMS Segment Managers

Segment Manager

Description

DOS

The standard MS-DOS* disk partitioning scheme. It is the most commonly used partitioning scheme for Linux, NetWare®, Windows*, OS/2*, BSD, Solaris* X86, and UnixWare*.

GPT (Globally Unique Identifier (GUID) Partitioning Table)

A partitioning scheme used for IA-64 platforms, as defined in the Intel* Extensible Firmware Interface (EIF) Specification. It is not compatible with DOS, Windows, or OS/2 systems.

The GUID is also known as Universally Unique Identifier (UUID). The GPT combines time and space descriptors to create this unique 128-bit tag for the disk and its segments.

S/390

A partitioning scheme used exclusively for System/390 mainframes.

Cluster

A partitioning scheme for high-availability clusters. It provides a GUID for the disk, creates an EVMS container for the shared cluster devices, and specifies a node ID for the node that owns the device and the cluster ID.

BSD

A partitioning scheme for BSD UNIX*.

MAC

A partitioning scheme for Mac-OS partitions.


Disk Segments

After you initialize the disk by adding a segment manager, you see metadata and free space segments on the disk. You can then create one or multiple data segments in a disk segment.

Table 4.2. Disk Segment Types

Segment Type

Description

Metadata

A set of contiguous sectors that contain information needed by the segment manager.

Free Space

A set of contiguous sectors that are unallocated or not in use. Free space can be used to create a segment.

Data

A set of contiguous sectors that has been allocated from a disk. The segment might be in use for a volume or a software RAID.



SUSE® Linux Enterprise Server Storage Administration Guide 10