The Enterprise Volume Management System (EVMS) 2.5.5 management tool for Linux is an extensible storage management tool that integrates all aspects of volume management, such as disk partitioning, the Logical Volume Manager (LVM), the Multiple-Disk (MD) manager for software RAIDs, the Device Mapper (DM) for multipath I/O configuration, and file system operations.
EVMS provides the following benefits:
An open source volume manager
A plug-in framework for flexible extensibility and customization
Plug-ins to extend functionality for new or evolving storage managers
Support for foreign partition formats
Cluster-aware
EVMS abstracts the storage objects in functional layers to make storage management more user-friendly. The following table describes the current EVMS plug-in layers for managing storage devices and file systems:
Table 1.1. EVMS Plug-In Layers¶
Storage Managers |
Description |
Plug-Ins |
---|---|---|
Device |
Manages the physical and logical devices |
Device Mapper (DM) |
Segment |
Manages the partitioning of physical and logical devices into smaller segments of free space. Segment managers can be stacked. For example, a cluster segment can contain other storage objects or volumes. |
Uses Device Mapper (DM) Segment managers include DOS, GPT, System/390 (S/390), Cluster, BSD, Mac, and BBR For more information, see Section 4.1, “Understanding Disk Segmentation”. |
Regions |
Manages the combination of multiple storage objects |
LVM/LVM2 for containers and region, MD for RAIDs, and DM for multipath I/O |
EVMS Features |
Manages EVMS features |
Drive linking (linear concatenation), Bad Block Relocation (BBR), and Snapshot |
File System Interface Modules (FSIM) |
Manages the interface between the file system managers and the segment managers |
For information, see Section 1.3, “Supported File Systems”. |
Cluster Manager Interface Modules |
Manages the interface between the cluster manager and the file systems and devices |
HeartBeat 2 |
EVMS supports the following Linux file systems:
EXT3
ReiserFS
XFS
OCFS2
JFS
EXT2
Swap
NTFS (read only)
FAT (read only)
For more information about file systems supported in SUSE Linux Enterprise Server 10, see the SUSE Linux Enterprise Server 10 Installation and Administration Guide..
The Novell Storage Services (NSS) file system is also supported when used with the Novell Open Enterprise Server 2 for SUSE Linux Enterprise Server 10 SP1 (or later versions of OES 2 and SLES 10).
The File System Primer describes the variety of file systems available on Linux and which ones are the best to use for which workloads and data.
EVMS uses the following terminology in the EVMS user interface:
Table 1.2. EVMS Terms¶
EVMS creates a unified namespace for the logical volumes on your system in the /dev/evms
directory. It detects the storage objects actually present on a system, and creates an appropriate device node for each one, such as those shown in the following table.
Table 1.3. Device Node Location¶