Implementing Network Backup

Saturday, April 08, 2006

Today the amount of data is increasing at an alarming rate and backing it up has become a major challenge for system administrators. As a result, the backup setup requirements have changed. Organizations now need backup solutions that can scale up as their data grows. They can't depend upon a solution that limits itself to single servers. That's where network backup solutions come into play. This is a new trend in the backup industry, and offers several benefits. For one, it improves the manageability of your entire backup setup, since you're no oscillating between different servers to backup their data. Everything's done over the network, including the management. Two, it automates some of the tasks that were earlier done manually. These give your backup administrators time to attend to other strategic issues. However, one needs to do quite a bit of planning before implementing such a solution. Here, we'll start off by helping you plan your backup strategy for network backup and then take you through a sample implementation of the same.

Planning backups
The first step in this is of course to analyze your organizational data. Analyze the type of data that you want to backup, how much data do you want to backup, and how much is your data expected to grow in the future.

How much time does your current backup take, and how much do you expect to reduce it by when it moves on the network. Next step is to decide which business data is more important to your company. One possible categorization of the value of data in your organization can be as follows:

Extremely Important Data: Identify data without which your organization can't function. This would include things like orders details, unpaid bills, proposals under negotiation, account statements of the clients, salary information, etc.

Moderately important: Data that is critical, but can be rebuilt with time and from other sources as well. This would include other accounting data and HR information, central database.

Lesser Important: This would be departmental data.

Unimportant: Personal data of users (Pictures, MP3s, videos, etc) is unimportant from an organization's point of view.

Backup Scenarios 
Once you've categorized the data, you will have a clear idea of just how much data needs to be backed up. Based on this, the next step is to look at the various types of backup scenarios that are possible. Let's look at some of them.

Server backup 
This is the oldest and simplest of all backup scenarios, and is applicable to departmental backups or  small businesses. In this, all users have to store their official data on servers and not on their personal machines.

You would then install a tape drive on the server and follow the usual routine of backing up the data to tape. Since all the important data is lying on the server, you don't really need to worry about the clients. Even if they lose data, it can be retrieved from tapes.

The real challenge is in ensuring that users do use the server for storing all their data. It also means that the traffic on the servers will be quite high, so their configuration must be able to handle the load. The challenge here would be to backup the users' email. That's where the next level comes into play. 

Large network backup
Today, it is normal for desktop systems to have 40-80 GB hard drives, and users store most of their data to it. For medium to large enterprise networks, which have a sizable number of such clients, following the usual server based backup routine is not feasible. At the backend also, the number of servers has also increased in these organizations. Therefore, it can become quite a nightmare to put a tape drive on each server and backup data from it. At this stage, you must consider going for network backup, which would create a separate backup server to collect data from all the other servers and clients.

So a server connected to the backup devices would take the backup from the other machines (clients/ servers) with the help of backup agents, which are running on machines that need to be backed up. 

Configure Netbackup 6.0 using a user-friendly wizard, which makes the configuration easy

Personal backups
This is a typical environment for 5-20 users, where no central file server is used. In this case, the backup has to be done on each machine using a common shared device or even individual backup devices. You can even use a CD or DVD-writer for this purpose, though given today's larger hard disks, you would have to use quite a large number of CDs if you want to back up full hard disks every time. Therefore you can use DVD instead of CDs, which these days have become quite affordable. Whichever of the above you decide to choose, the machines to be backed up, as well as the applications, the files and the folders have to be identified first.

When to backup
Backup is a resource hungry process, which stresses both your systems and your network. Typically you do not backup when the network is being used for regular office work, because the data flow over the network for backup will slow down the regular office work drastically. The usual option for doing back up is to choose a time when the rest of the office is not working such as lunchtime or after office hours, or even week ends. Everyone wants to back up at the least time, but faster backup media and drives cost more than slower solutions.

Therefore, full backups should be done on weekends when there is no user load and the backup window is about 24-36 hrs. Incremental backups can be done on weekdays, after office hours with a backup window of 3-12 hrs. This is done by the backup software itself if you set your backup operation on incremental mode. Here, the size of the data would be small compared to full backup. Thus it takes lesser time too.

How to do a network backup
In order to demonstrate how network backup is setup, we took a product of this class and deployed it. This was the Symantec NetBackup 6.0, which is an enterprise class network backup software. 

It's very easy to setup and lets you manage all backup operations from a single point. It allows you to take backups from both server and desktop class machines and a host of Operating Systems. These include various versions of Windows, UNIX, Linux, and NetWare. It supports all types of tape libraries and disk based backup devices. The administrator can initiate backups remotely, and even setup periodic or calendar-based backup schedules to perform automatic, unattended backups for clients across the network.

This can be useful to perform backups when the network is free, such as lunch-time, after-office hours, weekends, etc. You can take full backup from all the servers and clients or do incremental (backing up only the files that have changed since the last backups. Everything in NetBackup can be administered through policies. For instance, you can define a policy, which will determine whether a user is allowed to perform restore operations or not. The main component of NetBackup is the Media Manager, which manages all the storage devices. To check its functionality, we used it to control backup operations on a tape library.

The Server Setup
The server that connects to the tape library has to be made as the Master Server. For this, you have to install the NetBackup server 6.0 on that machine. The software has three install options, called the Master Server, Media Server, and Remote Administration Console. Select the first option. The installation will prompt you to enter your media server's name, which by default is the same as the machine's name. Don't change it. Once installed, you need to install the Veritas device drivers, which will automatically install the drivers for the connected tape library.

Next, the Master Server has to be configured to take the backup jobs from clients and servers running on your network, and back them up to the tape library. For this, the Removable Media Service or RMS has to be disabled from services. After that, run the NetBackup Administration Console from the Start Menu. Before starting it, you will be asked to enter the server's name where you have installed the Master Server. In our case, it was on the same machine, so we use used 'localhost' instead of the server's name. Then left pane of the console contains a node for each major area of NetBackup administration. Clicking a node displays information related to that node in the Details pane on the right. NetBackup is very easy to setup using its 'Get Started' wizard.

From the right pane, select 'Getting Started'. This wizard is used if you are configuring NetBackup for the first time. It will take you through the essential steps and other wizards to get you up and running with a working NetBackup configuration. It includes wizards to configure your storage devices, volumes, configure Catalog Backup, create backup policies, and configure storage devices.

Backup process is initiated automatically from the master server according to defined policies

Device setup
There's a device configuration wizard to guide you through the entire process of configuring a device and storage unit connected to the master server. It automatically detects the connected tape library and fetches the drive parameters, which is required by the master server to manage the tapes inventory. The next part is to configure volumes from the backup data; a volume pool is created to add volumes that the administrator can assign to explicit backup policies or schedules. The Volume Configuration Wizard guides you through the entire process and configuring removable media accordingly. Another important part of NetBackup is configuring catalog backup. It helps you set up your catalog backups, which are essential for recovering your data in case of a server failure or crash. This basically creates an index file, which helps the Master Server recover data quickly from the storage media.  

Backup policy
This wizard lets you create automated backup policies, which allow you to take scheduled backups of your connected machines on tapes. The Backup Policy wizard configuration wizard adds a backup policy to your configuration. Besides these, there are several other useful wizards in NetBackup. There's the Import Images wizard, which can import backups that have expired, backups from another NetBackup server, or backups that were written by Backup Exec for Windows. It imports images in a two-part process. First it creates a list of expired catalog entries for the backups on the imported volume. No actual import occurs in this process. In the next process images are selected from the expired list of image generated from process one and then you can import the Netbackup. There's also a wizard to configure shared devices. This let's you configure NetBackup to use shared drives or reconfigure an existing shared drive. There's another wizard for recovering the catalog, which lets you recover data from the backup media when disaster strikes.

Client Setup
NetBackup has client agents for all types of clients including Windows, Unix, Solaris and even 64-bit OSs . You need to install it on all the clients to backup data remotely from them. The backup process can be initiated directly from the client, or you can setup a schedule backup policy on the Master Server so that NetBackup can automatically take backup of that machine on the tape periodically. If you want to take backups from the clients directly, then lunch “Backup, Archive and Restore” program and select the data that you want to take backup and then click the backup button. This will open a backup options window; here select the master server, where you Netbackup server and backup devices are connected. Finally click 'Start' button to initiate the backup process.

Sanjay Majumder

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