Chapter 1. Introduction to NetWorker
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## Chapter 1. Introduction to NetWorker

Everyone knows the importance of backing up computer systems to protect from the loss of valuable data. In a networked environment, where the number of files grows as systems are added to the network, the need to protect against loss of data becomes crucial.

IRIX NetWorker is a software product that reliably protects files against loss across an entire network of systems. NetWorker saves valuable administrator time by speeding and simplifying daily backup operations. An easy-to-use graphical user interface guides you through administering and configuring your network for scheduled backups. As NetWorker backs up your data, it creates a database of the saved data, making it easy to locate a file for recovery. Furthermore, as the network and number of files expand, NetWorker has the capacity and performance to handle the load.

Whether you need to recover an entire filesystem or a single file, NetWorker tracks the location of the files on the backup volumes and requests the ones you need by name. You do not have to think about which backups are on which backup volumes. All you need to do is mount the requested backup volume in a NetWorker server device to recover the desired files. Loading and mounting volumes is automatic if you are using an autochanger. An autochanger is a device that can move media among various components located in the device, including slots, media drives, media access ports, and transports; examples are jukeboxes and tape libraries.

This chapter introduces

- versions and compatibility

- NetWorker basics

- the NetWorker client/server model

- backing up clients

- recovering lost files

- backup devices and media

## Versions and Compatibility

NetWorker 4.1.1 server software runs on IRIX 5.3 and 6.x. NetWorker requires the base release of the software and enough disk space for the installation and the index files. NetWorker uses about 1 MB of index space for each gigabyte of backup.

The NetWorker 4.1.1 client software runs on IRIX 4.x, 5.3, and 6.x; see the IRIX NetWorker Release Notes for more information. NetWorker 4.1.1 is fully compatible with all index and resource files from NetWorker version 4.0.2 and 4.0.2A.

| Note: For information on licenses and NetWorker products, see“Enabling Server Software” in Chapter 2, “Installing NetWorker.”

| Caution: Once you have upgraded from NetWorker version 1.x to 4.1.1, you cannot go back because of the changes made to the index files during the upgrade. Index files from 4.0.2 and 4.0.2A are compatible with 4.1.1.

## NetWorker Basics

A set of files backed up by a NetWorker client is called a save set. Backup volumes are the media to which NetWorker backs up data and are recognized and managed by NetWorker. Volume pools are used by NetWorker to sort specific data to preselected backup volumes.

The backup volume names and client save sets are maintained in two indexes on the server: the file index and the media index. NetWorker uses these two indexes to track file backups to specific backup volumes. The media manager works with the two indexes to track where the backups are located on the backup volumes, making it easy to recover lost files.

When backing up files, NetWorker may request that you mount a writable backup volume in the server device. When recovering files, NetWorker requests a specific backup volume by its name. All you need to do is mount the requested backup volume or volumes in the device(s) attached to the server. If you have a jukebox or other autochanger, the NetWorker TurboPak option, and a NetWorker Autochanger Software Module, NetWorker automatically loads the requested volume if it is stored in the autochanger.

## The NetWorker Client/Server Model

A client/server architecture is the key to the ability to support network-wide, heterogeneous backup and recover. NetWorker servers provide a backup and recover service: they receive files from NetWorker clients, store the files on backup volumes, and retrieve the files on demand.

A NetWorker server is a system equipped with one or more backup devices. The server responsibilities are to

- write files from many client systems to media

- maintain an index of information about all the files backed up and where they are stored

- allow the clients to browse the file index

- fill requests from clients to back up or recover files

- initiate automatic network-wide backups according to a specific schedule

- give notices about NetWorker events

The NetWorker clients are all the other systems on the network that use the backup and recover service provided by the server. Clients can be desktop workstations, PCs with small disk drives, or large systems with gigabytes of data.

The clients on the network have software installed that

- gives the client access to the server for backing up and recovering files

- allows the client to browse the online index on the server to select files for recovery

A single NetWorker server can provide the backup and recover services to many client systems.

## Backing Up Clients

NetWorker performs network-wide system backups. Such backups are more efficient and easier to maintain than local backup because of these NetWorker features:

- NetWorker has preconfigured backup schedule suitable for most small to medium-sized networks. You can easily edit this schedule using the NetWorker X™ Window System interface. You may create multilevel backups spanning any time period: weekly, monthly, bimonthly, or quarterly.

- A sophisticated media manager prompts you for all of its media requirements. When a volume is needed for backup or file recovery, NetWorker sends a message via its window-based status monitor or by electronic mail.

- NetWorker enables you to back up to premounted multiple devices or to a jukebox for unattended backups.

- The filesystems or individual files being backed up can span multiple backup volumes, or numerous filesystems and files can be saved to the same backup volume.

- The online backup feature allows you to perform backups while server and client systems remain in operation.

- The backups from many clients take place in parallel. This feature keeps a steady stream of data supplied to the backup device or devices so they can operate at full speed. The parallel backup option also ensures that no single client can monopolize the server and prevent other clients from accessing the server. With IRIX NetWorker and the TurboPak, NetWorker can back up to several backup devices at once, thus optimizing server performance.

- You can separate the media containing your full backups from media containing non-full backups.

- You can sort data during backup to preselected volume pools.

## Recovering Lost Files

The NetWorker online index and media manager work together to expedite the recovery of lost files. The basic procedure for recovering files is as follows:

- Users browse the online index of previous file backups to identify the lost files and mark the files they want to recover, using the graphical user interface.

- The NetWorker media manager determines which backup volumes are needed to recover the files and requests only the ones it needs for the recovery.

- Once the volume is loaded in the server device, the files are recovered to the client.

- The optional NetWorker Support for Jukeboxes automates tape loading operation for fast recoveries.

## Backup Devices and Media

NetWorker supports a number of backup devices. For the current list, see the IRIX NetWorker Release Notes.

| Caution: A no-rewind tape backup device is required (except for optical drives) because NetWorker writes a file mark on the backup volume at the end of each backup and then appends data onto the volume based on the position of the file mark. If the device rewinds the media, the file mark position is lost and previously written data is overwritten by the next backup.

To work with IRIX NetWorker, digital linear tape (DLT) drives in all peripherals must have Silicon Graphics personalities. If the DLT is not bought from Silicon Graphics, you must request the correct version of the firmware from the vendor.

| Note: DLT2700 stackers that are not from Silicon Graphics do not work with IRIX NetWorker.

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IRIX™ NetWorkerŽ Administrator's Guide |  | Chapter 2. Installing NetWorker