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 consistency
Site consistency means that at any point in time, the data at each site is consistent with the application for a given set of volumes. A site-consistent volume must have at least one plex, or mirror, on each configured site in the disk group. The site consistency is ensured by detaching a site when a site-consistent volume loses its last complete plex on that site. The site detach detaches all the plexes on that site and also disallows further configuration updates to the configuration copies on that site. Turn on this behavior by setting the siteconsistent attribute to on on the desired volumes.
If you set the siteconsistent attribute to off, only the plex that fails is detached. The plexes for the remaining volumes on that site are not detached.
The siteconsistent attribute is also present at the disk group level and can be used to turn on or off the site consistency functionality in the disk group boundary. In addition, if you turn on the siteconsistent attribute for a disk group, each new volume created in the disk group inherits the site consistency of the disk group, by default. Setting the siteconsistent attribute on a disk group does not affect siteconsistent attributes for existing volumes. You can also control the site consistency on individual volumes.
By default, a volume inherits the value that is set on its disk group.
By default, creating a site-consistent volume also creates an associated version 20 DCO volume, and enables Persistent FastResync on the volume. This allows faster recovery of the volume during the reattachment of a site.
Before setting site consistency on a disk group, be sure to meet the following requirements:
A license enabling the Site Awareness feature must be purchased for each host in the Remote Mirror configuration.
At least two sites must be configured in the disk group before site consistency is turned on.
All the disks in a disk group must be registered to one of the sites before you can set the siteconsistent attribute on the disk group.