Veritas NetBackup™ Administrator's Guide, Volume II
- NetBackup licensing models and the nbdeployutil utility
- Additional configuration
- About dynamic host name and IP addressing
- About busy file processing on UNIX clients
- About the Shared Storage Option
- About configuring the Shared Storage Option in NetBackup
- Viewing SSO summary reports
- About the vm.conf configuration file
- Holds Management
- Menu user interfaces on UNIX
- About the tpconfig device configuration utility
- About the NetBackup Disk Configuration Utility
- Reference topics
- Host name rules
- About reading backup images with nbtar or tar32.exe
- Factors that affect backup time
- NetBackup notify scripts
- Media and device management best practices
- About TapeAlert
- About tape drive cleaning
- How NetBackup reserves drives
- About SCSI persistent reserve
- About the SPC-2 SCSI reserve process
- About checking for data loss
- About checking for tape and driver configuration errors
- How NetBackup selects media
- About Tape I/O commands on UNIX
About SCSI reservation conflicts
The NetBackup Automatic Volume Recognition process (avrd) manages access to tape devices. A properly configured NetBackup environment and properly configured tape devices should not receive a reservation conflict message from a tape drive. When avrd starts, it issues an SPC-2 SCSI release to all configured, nondisabled tape drive paths that are currently in the Up state. The command releases all devices that were SPC-2 reserved at the time of a system restart or crash. The SCSI release command returns tape devices to general availability after a system crash.
If the avrd process receives a reservation conflict message, it changes the status of the device to PEND. It also writes the following message in the system log:
Reservation Conflict status from DRIVENAME (device NUMBER)
Also, the NetBackup Administration Console Device Monitor or the output from the vmoprcmd command shows PEND in the Control column.
If a conflict occurs, a reservation problem can exist. If the HBA that reserves the drive is unavailable (for example, due to a system crash or hardware failure), it cannot release the reservation. NetBackup cannot release or break an SPC-2 SCSI reservation automatically. Force a release or break the reservation to make the drive available, even for a failover server in a cluster environment.
When the conflict is resolved, the following message is written to the log:
Reservation Conflict status cleared from DRIVENAME (device NUMBER)