Solstice Backup 5.1 Administration Guide

Backup Daemons and Programs

This section provides a description of the Backup server and storage node daemons and programs, which contact the client for a backup and maintain the server's client file index and media databases. (For more information about storage nodes, see "Backup Operations With Storage Nodes ".) The Backup man pages contain further details about the Backup daemons and programs. Table A-1 describes the server daemons and programs.

Table A-1 Functions of Server Daemons and Programs


Daemon/Program	Function
`ansrd`	This daemon monitors an active `save` or `recover` session; agent process spawned by `nsrd` in response to a `save` or `recover` session.
`asavegrp`	This daemon monitors the progress of individual save sets; agent process invoked by `savegrp`.
`nsrck`	This daemon checks the consistency of the client file index; invoked by `nsrd` whenever the consistency of the client file index needs to be confirmed.
`nsrd`	This daemon provides an RPC-based `save` and `recover` service to Backup clients; master Backup daemon.
`nsrim`	This daemon automatically manages the server's client file index; invoked at the end of a `savegrp`.
`nsrindexd`	This daemon provides a method for inserting entries in the client file index based on information passed by the `save` program.
`nsrmmd`	This daemon provides device support, generates mount requests, and multiplexes save set data during a multi-client backup (`nsrd` can start several `nsrmmd` daemons, up to the number specified in the device's Target Sessions attribute); media multiplexor daemon.
`nsrmmdbd`	This daemon provides media and save set database management services to the local `nsrd` and `nsrmmd` daemons and records entries in the media database; media management database daemon.
`savegrp`	This program runs a group of Backup clients through the `save` process.

The nsrd master Backup server daemon is responsible for several tasks:

Starting other daemons
Allocating media daemons on server and storage node machines
Authorizing backup and recover services for the client
Contacting clients for scheduled backups
Maintaining Backup configuration information
Monitoring backup and recover sessions
Maintaining server statistics and message logs

The nsrd Backup server daemon calls on the nsrexecd Backup client daemon and several client-side programs when it receives a scheduled or on-demand backup request. The ansrd temporary server agent daemon starts on the Backup server to monitor the progress of the backup session. Table A-2 describes the client-side daemons and programs.

Table A-2 Functions of Client Daemons and Programs


Daemon/Program	Function
`nsrexecd`	This daemon authenticates the Backup server's remote execution request and executes the `save` and `savefs` commands on the client.
`recover`	This program browses the Backup server's client file index and restores the specified file to primary disk storage.
`save`	This program sends specified files in a multiplexed data stream to the Backup server for backup to media by `nsrmmd` and entry in the client file indexes and media database by `nsrindexd`.
`savefs`	This program sends information about the save sets to back up for the client; identifies save set data modified since the previous level `save`.