Troubleshooting guide

Appendix A, Functional Overview 257
Media Manager Functional Description
Media and Device Management Process
When the Media Manager daemons are running, NetBackup, Storage Migrator (UNIX
only), or other users can initiate data storage or retrieval by sending a request for the
required media ID to the Media Manager device daemon, ltid (Figure 15). ltid
determines the location of the requested media ID by sending a query to the Media
Manager volume daemon, vmd. The volume daemon then returns the information it has
about the media, including: robot number, robot type, host, slot, and barcode.
If the media is in a robot, ltid sends a mount request to the robotic daemon that controls
the robot. The robotic daemon then chooses an available drive, mounts the media, and
sets a drive busy status in memory shared by itself and ltid. If it receives another mount
request, ltid checks that status to determine which (if any) drives are available. Drive
busy status also appears in the Device Monitor (and xdevadm).
Assuming that the media is physically in the robot, the media is mounted and the
operation proceeds. If the media is not in the robot, ltid sends a mount request, which
appears as a pending request in the Device Monitor (and xdevadm). An operator must
then insert the media in the robot and use the appropriate Device Monitor (or xdevadm)
command to resubmit the request so the mount request can occur.
A mount request is also issued if the media is for a nonrobotic (standalone) drive and the
drive does not contain media that meets the criteria in the request. If the request is from
NetBackup and the drive does contain appropriate media, then that media is
automatically assigned and the operation proceeds. See the NetBackup System
Administrator’s Guide for more information on NetBackup media selection for nonrobotic
drives.
When a robotic volume is added or removed through a mailslot (or inport/outport), the
media management utility communicates with the appropriate robotic daemon to verify
the volume location and/or barcode. The media management utility (through a library or
command-line interface) also calls the robotic daemon for robot inventory operations