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
Recovering from a loss of site connectivity
Warning:
To avoid a potential loss of data, it is recommended that you configure Veritas Cluster Server to handle network split-brain.
If the network links between the sites are disrupted, the application environments may continue to run in parallel, and this may lead to inconsistencies between the disk group configuration copies at the sites. If the parallel instances of an application issue writes to volumes, an unrecoverable data loss may occur and manual intervention is needed. To avoid data loss, it is recommended that you configure the VCS fencing mechanism to handle network split-brain situations. When connectivity between the sites is restored, a serial split-brain condition will be detected between the sites. One site must be chosen as having the preferred version of the data and the disk group configuration copies. The data from the chosen site is resynchronized to the other site. If new writes are issued to volumes after the network split, they are overwritten with the data from the chosen site. The configuration copies at the other sites are updated from the copies at the chosen site.
At the chosen site, use the following commands to reattach a site and recover the disk group:
# vxdg -g diskgroup -o overridessb reattachsite sitename # vxrecover -g diskgroup
In the case that the host systems are configured at a single site with only storage at the remote sites, the usual resynchronization mechanism of VxVM is used to recover the remote plexes when the storage comes back on line.
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