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
Disk group failure policy
The local detach policy by itself is insufficient to determine the desired behavior if the master node loses access to all disks that contain copies of the configuration database and logs. In this case, the disk group is disabled. As a result, any action that would result in an update to log/config copy will also fail from the other nodes in the cluster. In release 4.1, the disk group failure policy is introduced to determine the behavior of the master node in such cases.
Table: Behavior of master node for different failure policies shows how the behavior of the master node changes according to the setting of the failure policy.
Table: Behavior of master node for different failure policies
Type of I/O failure | Leave (dgfailpolicy= leave) | Disable (dgfailpolicy= dgdisable) | Request Leave (dgfailpolicy= requestleave) |
---|---|---|---|
Master node loses access to all copies of the logs. | The master node panics with the message "klog update failed" for a failed kernel-initiated transaction, or "cvm config update failed" for a failed user-initiated transaction. | The master node disables the disk group. | The master node leaves the cluster, after VCS handles all the applications dependent upon shared storage by either gracefully stopping them or failing them over to other nodes of the cluster. |
The behavior of the master node under the disk group failure policy is independent of the setting of the disk detach policy. If the disk group failure policy is set to leave, all nodes panic in the unlikely case that none of them can access the log copies.
If the disk group failure policy is set to requestleave, the master node gracefully leaves the cluster if the master node loses access to all log/config copies of the disk group. If the master node loses access to the log/config copies of a shared disk group, Cluster Volume Manager (CVM) signals the CVM Cluster Veritas Cluster Server agent. Veritas Cluster Server (VCS) attempts to take offline the CVM group on the master node. When the CVM group is taken offline, the dependent services groups are also taken offline. If the dependent applications managed by VCS cannot be taken offline for some reason, the master node may not be able to leave the cluster gracefully.
The vxdg command can be used to set the failure policy on a shared disk group.
More Information
Setting the disk group failure policy on a shared disk group