Veritas™ Volume Manager Administrator's Guide
- Understanding Veritas Volume Manager
- VxVM and the operating system
- How VxVM handles storage management
- Volume layouts in VxVM
- Online relayout
- Volume resynchronization
- Dirty region logging
- Volume snapshots
- FastResync
- Provisioning new usable storage
- Administering disks
- Disk devices
- Discovering and configuring newly added disk devices
- Discovering disks and dynamically adding disk arrays
- How to administer the Device Discovery Layer
- Changing the disk-naming scheme
- Adding a disk to VxVM
- Rootability
- Displaying disk information
- Removing disks
- Removing and replacing disks
- Administering Dynamic Multi-Pathing
- How DMP works
- Administering DMP using vxdmpadm
- Gathering and displaying I/O statistics
- Specifying the I/O policy
- Online dynamic reconfiguration
- Reconfiguring a LUN online that is under DMP control
- Creating and administering disk groups
- About disk groups
- Displaying disk group information
- Creating a disk group
- Importing a disk group
- Moving disk groups between systems
- Handling cloned disks with duplicated identifiers
- Handling conflicting configuration copies
- Reorganizing the contents of disk groups
- Destroying a disk group
- Creating and administering subdisks and plexes
- Displaying plex information
- Reattaching plexes
- Creating volumes
- Types of volume layouts
- Creating a volume
- Using vxassist
- Creating a volume on specific disks
- Creating a mirrored volume
- Creating a striped volume
- Creating a volume using vxmake
- Initializing and starting a volume
- Using rules and persistent attributes to make volume allocation more efficient
- Administering volumes
- Displaying volume information
- Monitoring and controlling tasks
- Reclamation of storage on thin reclamation arrays
- Stopping a volume
- Resizing a volume
- Adding a mirror to a volume
- Preparing a volume for DRL and instant snapshots
- Adding traditional DRL logging to a mirrored volume
- Enabling FastResync on a volume
- Performing online relayout
- Adding a RAID-5 log
- Creating and administering volume sets
- Configuring off-host processing
- Administering hot-relocation
- How hot-relocation works
- Moving relocated subdisks
- Administering cluster functionality (CVM)
- Overview of clustering
- Multiple host failover configurations
- CVM initialization and configuration
- Dirty region logging in cluster environments
- Administering VxVM in cluster environments
- Changing the CVM master manually
- Importing disk groups as shared
- Administering sites and remote mirrors
- About sites and remote mirrors
- Fire drill - testing the configuration
- Changing the site name
- Administering the Remote Mirror configuration
- Failure and recovery scenarios
- Performance monitoring and tuning
- Appendix A. Using Veritas Volume Manager commands
- Appendix B. Configuring Veritas Volume Manager
Layered volumes
A layered volume is a virtual Veritas Volume Manager object that is built on top of other volumes. The layered volume structure tolerates failure better and has greater redundancy than the standard volume structure. For example, in a striped-mirror layered volume, each mirror (plex) covers a smaller area of storage space, so recovery is quicker than with a standard mirrored volume.
Figure: Example of a striped-mirror layered volume shows a typical striped-mirror layered volume where each column is represented by a subdisk that is built from an underlying mirrored volume.
The volume and striped plex in the "Managed by User" area allow you to perform normal tasks in VxVM. User tasks can be performed only on the top-level volume of a layered volume.
Underlying volumes in the "Managed by VxVM" area are used exclusively by VxVM and are not designed for user manipulation. You cannot detach a layered volume or perform any other operation on the underlying volumes by manipulating the internal structure. You can perform all necessary operations in the "Managed by User" area that includes the top-level volume and striped plex (for example, resizing the volume, changing the column width, or adding a column).
System administrators can manipulate the layered volume structure for troubleshooting or other operations (for example, to place data on specific disks). Layered volumes are used by VxVM to perform the following tasks and operations:
Creating striped-mirrors |
See the vxassist(1M) manual page. |
Creating concatenated-mirrors |
See the vxassist(1M) manual page. |
Online Relayout |
See the vxassist(1M) manual page. See the vxrelayout(1M) manual page. |
Moving RAID-5 subdisks | See the vxsd(1M) manual page. |
Creating Snapshots | See the Veritas Storage Foundation Advanced Features Administrator's Guide See the vxassist(1M) manual page. See the vxsnap(1M) manual page. |