Details:
After a NetBackup process is done with the media, an SCSI release is issued as part of the unmount operation. This release will free the device for access by another Host Bus Adaptor (HBA).
In addition, at the beginning of the startup process avrd issues an SCSI release to all configured tape devices that are currently in the Up state. This is done to release devices that were reserved at the time of a system re-boot or crash. The SCSI release command will return tape devices to general availability after a system crash.
Error Recovery:
To recover a device that is reserved by an HBA that crashes or otherwise was unable to issue the SCSI release command, you can use the following option for the Media Manager vmoprcmd command:
vmoprcmd -crawlreleasebyname drive_name
This option requests all hosts that are registered to use the drive to release the drive (using the SCSI release command).
Issue the vmoprcmd command on the host that is the device allocator (DA host) or use the -h option on the command to specify the DA host.
Caution: You can use this command after a PEND status has been displayed in Device Monitor in the NetBackup Administration Console, but do not issue this command during backups. See "Drive Status List of the Device Monitor" on page 65 of the "NetBackup 4.5 Shared Storage Option System Administrator's Guide for UNIX and Windows".
See your Media Manager system administrator's guide for the complete syntax and more information on using the vmoprcmd command.
SCSI Reserve/Release Logging and Conflict Notification:
The bptm process logs all SCSI reserve/release commands. The bptm log should be checked on all hosts to ensure the SCSI reserve operation is being logged (look for SCSI RESERVE in the log).
The avrd process monitors all tape devices. NetBackup manages access to tape devices, such that a properly configured system will not receive the RESERVATION CONFLICT status from a tape device.
Reservation Conflict:
If avrd gets a RESERVATION CONFLICT status, avrd changes the status of the device to PEND and writes the following message in the system log:
Reservation Conflict status from DRIVENAME (device NUMBER)
When the conflict is resolved, the following message will be written to the log:
Reservation Conflict status cleared from DRIVENAME (device NUMBER)
If this conflict occurs, some sort of mis-configuration is present (for example, the tape drive is reserved, but should not be) and the configuration problem should be corrected. A possible cause of this conflict is if an operating system crashes or a hardware failure has left a device reserved (see "Issuing the Release" on page 75 of the "NetBackup 4.5 Shared Storage Option System Administrator's Guide for UNIX and Windows").
Also in the Device Monitor or the output from the vmoprcmd command, PEND in the Control column means that a reservation conflict has occurred. See "Drive Status List of the Device Monitor" on page 65 of the "NetBackup 4.5 Shared Storage Option System Administrator's Guide for UNIX and Windows".
Bob Stump
Incorrigible punster -- Do not incorrige
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