Veritas NetBackup™ Administrator's Guide, Volume II
- NetBackup licensing models and usage reporting
- How capacity licensing works
- Creating and viewing the licensing report
- Reviewing a capacity licensing report
- Reconciling the capacity licensing report results
- Reviewing a traditional licensing report
- Reviewing an NEVC licensing report
- Additional configuration
- About dynamic host name and IP addressing
- About busy file processing on UNIX clients
- About the Shared Storage Option
- DELETE 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 the SPC-2 SCSI reserve process
The NetBackup process issues an SPC-2 SCSI reserve command to the tape drive that contains the media. (The process can be bptm, bprecover, or bpbackupdb.) If the device is not reserved, NetBackup acquires a reservation. The drive does not process commands from any other host bus adapters (HBAs) until NetBackup releases the reservation or the reservation is broken. If the reservation fails, NetBackup fails the job.
The reservation does not prevent other applications on the host that has the reservation from using the same device and from causing data loss. For example, if a user on the same host issues a UNIX mt command, the mt command can take control of the drive.
After the NetBackup process finishes with the media, it issues an SPC-2 SCSI command to release the reservation during the unmount operation. The release frees the device for access by another HBA.
SCSI reserve does not provide a method to determine if a device is reserved. Only the reservation owner (the host bus adapter) can release the reservation. However, these limitations do not interfere with NetBackup operations in most environments.