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
About site-based allocation
Site-based allocation policies are enforced by default in a site-configured disk group. Site-based allocation requires that each volume has at least one plex at each site that is configured in the disk group. When a new volume is created in a site-configured disk group, the allsites attribute set to on, by default. The allsites attribute indicates that the volume must have at least one plex on each configured site in the disk group. For new volumes, the read policy is set to siteread by default.
If mirroring across sites is not required, or is not possible (as is the case for RAID-5 volumes), specify the allsites=off attribute to the vxassist command. If sites are configured in the disk group, a plex will always be confined to a site and will not span across sites. This enforcement cannot be overridden.
Before adding a new site to a disk group, be sure to meet the following requirements:
Disks from the site being added (site tagged) are present or added to the disk group.
Each existing volume with allsites set in the disk group must have at least one plex at the site being added. If this condition is not met, the command to add the site to the disk group fails. If the -f option is specified, the command does not fail, but instead it sets the allsites attribute for the volume to off.
Note:
By default, volumes created will be mirrored when sites are configured in a disk group. Initial synchronization occurs between mirrors. Depending on the size of the volume, synchronization may take a long time. If you do not need to perform an initial synchronization across mirrors, use init=active with the vxassist command.