Tape Backup (part 2)

Sure, the initial backup can take quite a while to complete and it consumes as much disk space as you would expect it to. But as files that have been previously backed up are modified, the file is not re-copied to the DPM server; only the bytes in the file that have changed since the last backup are copied. This saves disk space on the DPM server and network bandwidth as well.¹⁰

The backup server may back up files on the mirrored servers every day, every hour, or at other defined intervals. Files on the backup server move to offline optical disk storage and eventually to tape storage, which is carried offsite. In the event that corrupted information is written to the mirrored servers, users can fall back to the backup server. If corrupted files are not detected and are written to the backup server, the most recent good file can be obtained from the optical disk or tape archives. This system can be totally automated and run continuously so that the most recent uncorrupted copy of a file can be traced back through the backup server to the archive, as necessary.⁴⁶

To recover, you might need to go to the most recent offline backup set.⁴⁶

The Real-Time Backup Edition contains everything you need to maintain a real-time backup of your mission-critical data. It includes a DataExchange license for two Pervasive PSQL database engines (for the primary and the backup) as well as a one-user count database license (for the backup). The DataExchange engines are restricted to one-way replication, and the replication network is restricted to two databases.⁵²

When you deploy DPM, you designate which volumes or shares on your network should be protected. At that time, Data Protection Manager makes a full backup of all of the files in the protected share or volume. In fact, you can even configure DPM to run backups hourly.¹⁰

If you have more than one local hard disk, copying your data to the other disk provides a certain amount of security. This protects you from a disk failure or and accidental erasure, but leaves you vulnerable if the computer itself is lost, stolen or badly damaged.⁸⁹

Network data mirroring duplicates the full or partial contents of a disk from one system to a disk on another system by sending data over a local- or wide-area network as the data changes. Comprehensive network data mirroring products, such as Qualix DataStar and Octopus DataStar from the Qualix Group, mirror user files, application files and database information for UNIX and Windows NT servers, respectively. Updates to all databases and files are copied as they are output to the source system disk, regardless of whether or not the files are open and in use on client machines. By continuously mirroring data to target systems at remote sites, network data mirroring accomplishes three important objectives.⁴⁴

Designate only trusted people as backup operators, and make sure their rights are limited to only those files and directories they need to back up. As an added precaution, you should make sure that an auditing system tracks and logs all activities of the backup operator.⁴⁶

Now, let's go back to the bigwig who deleted that file he needed for that afternoon's meeting. If Microsoft System Center Data Protection Manager runs hourly backups, the file will have been backed up -- even though it was only created recently. Not only that, there is even a user interface that allows users to perform their own restores without having to call you, the admin! Since the backup is disk-based, you don't even have to load a tape.¹⁰

If you want to back up an entire drive or drives, click to select the check boxes next to the drives you want to back up. If you want to back up specific files or folders on a drive, double-click the drive to expand it. Then continue to expand folders until the files or folders you want to back up are displayed. Next, click to select the check box next to each file and folder you want to back up. If you then want to select files on another drive, click Drives on the Window menu, and then expand the drive and click to select the check box next to each file and folder you want to back up. When you have finished selecting files and folders to be backed up, click Backup.¹⁹

Windows NT Backup backs up the selected data. When the backup is complete, click OK in the Backup Status dialog box. Quit Windows NT Backup to complete the process of making a backup on your Windows NT 4.0-based computer.¹⁹

In the Description box, type a description of the backup. Select the backup type you want to use, and then select the backup options you want to use for this backup.¹⁹

To access a snapshot, go to the directory where the file or directory you need to restore is (or was). Then change to the .snapshot directory. This directory is a special directory which is hidden most of the time. It will not show up when you run ls, but it IS there.⁵

To actually restore the files, change directory to the appropriate snapshot and then copy the file back to it's original location (or to an alternate location if desired) using standard unix commands.⁵

Magnetic tape is the workhorse of short-term backup. The media is relatively inexpensive, so it is reasonable to preform frequent indiscriminate backup of entire servers. The tape backup is a crucial first line of defense against a total disk failure, since the entire volume can be restored at once. Since data is accessed sequentially, it can take a considerable amount of time just to locate the file. The downside is that tape is not as reliable as other media and it has a considerably shorter shelf life, making it inappropriate for archival storage.⁸⁹

The traditional tape backup takes time, money and resources to schedule and manage backups, change disks and tapes, and transport them to a secure facility. To ensure your data is actually restorable, you must test all of your backup media to verify that they are labeled and cataloged properly, un-corrupted and free from physical damage. Most businesses that do their own tape backup, know that data restoration from tape is not reliable.⁷⁹

You never really realize how much is lost until you fire up that key program and it does not work the way it used to. Worse you may have lost that key program and its files.⁹²

If you run a small business, chances are you're saving important files to a server.But what happens when disaster strikes? Many people fail to realize that the loss of files could cripple their business. You can insure your office and equipment, but you can't insure files. Ipso facto, they are lost!⁹⁷

Another problem with traditional backups: In most cases, files that are open are not backed up. Shadow copy has made it possible to back up open files, but many backup applications, especially older ones, do not take advantage of shadow copy. But since DPM is fully shadow-copy-compliant, it can back up files whether they are open or not.¹⁰

Real-time backups take place at any time and must have a procedure for handling files that are open during backup.⁴⁶

Shah used data points showing that tape backups were becoming too time-intensive as data stores grew, plus an explanation that the company's distributed environment required separate tape drives for various systems, to convince the CEO to authorize a move to IBM's Tivoli Storage Manager (TSM) in 2003. Today, Mouser uses TSM to back up a multitude of applications and data, including IBM's UniVerse relational database management system, which houses the company's order entry and financial data, as well as its warehouse control system, graphics servers and file servers.⁴²

Automated backup systems include dedicated backup servers that automatically back up data to magnetic disk, jukebox tape libraries, and jukebox optical disk systems. They may provide hierarchical storage management functions as well. A typical automated system will run 24 hours a day and provide backup services for a number of clients (clients in this case are file and application servers that use the backup services). It provides centralized backup administration, data compression, security, and a number of other features specific to the clients it supports. The Arback and Boole & Babbage products also support remote vaulting. A list of vendors that make backup products is presented on the related entries page.⁴⁶

If a large number of mailboxes are active it is easy to confuse mailboxes and delete one by mistake. The Exchange Backup API supports full Exchange database backup only and does not support mailbox restore; therefore, some interesting methods have been developed to recover a lost mailbox.⁶⁶

Read this white paper if you are responsible for developing a disaster recovery plan for your higher education campus or computer lab. The paper provides information about how to efficiently use tape backup technology in a world rich with Apple workstations and servers.⁹

As always, it is important to choose an option that suits your business and financial situation, but it is imperative that your business has an effective and efficient data recovery plan that covers all possible situations. Offsite storage should be part of that recovery plan.⁷¹

New factors and increased focus in BC/DR planning: BC/DR strategies are affected by the increasing amount of business data being pushed into the mission-critical category, requiring continuous availability. Businesses are also aware that the dangers to their mission-critical data are greater than ever before. Not so long ago businesses had to plan for human error, technical glitches and, of course, natural disasters. Post 9/11, businesses must also plan for terrorist attacks that, as a November 2002 report from Illuminata put it, could "take out more than just a couple of floors of one data center."⁵⁶

Many companies are already backing up their main and branch office systems to tape, but what they don't understand is just how vulnerable their data and their business remains. This whitepaper explores the high cost, complexity and potentially dangerous shortcomings of a strategy based only on tape backup.⁹

CBL and other companies like it want your business, and they try to be helpful in multiple ways. Here's how you can minimize the chances of a tape backup failing in the first place, according to Doug Owens, managing director of CBL's San Diego laboratory and resident tape expert. Many of these same precautions apply to other backup systems as well.⁴⁷

Picture this: The air conditioners in your office malfunction over the weekend and your business servers overheat. Eventually, a fire starts and your computers, drives, and tape backup that were stored in the same location are unsalvageable due to the extreme heat, even by professional recovery services. Irreplaceable data is lost and there is nothing that can be done to retrieve it. An event such as this is completely unforeseen, but its consequence - data loss, is very much preventable. The solution is offsite data storage.⁷¹

A surprising majority of small businesses do not have a reliable backup system. Whether it be due to budget constraints of implementing an in-house backup server or just being unsure of how to implement backups to avoid disaster, many business owners don't realize that they are placing their own livelihood in jeopardy every day by not having a secure backup system. Unfortunately, some learn the hard way and only after a disaster understand the importance of safeguarding their business data. Why wait for disaster and pay thousands of dollars for an attempt to recover the data from a failed hard disk when you can protect yourself for as little as a dollar a day?⁸²

Enhanced Windows Backup uses Windows' built in backup engine called Windows Backup (ntbackup.exe) which provides state-of-the-art core backup technology. Enhanced Windows Backup substantially extends the capabilities of NTBackup, providing an effective integrated backup solution that can take on leading edge but expensive solutions like Backup Exec and Retrospect from companies like Veritas, Symantec and Dantz.⁴³

An integrated LAN attach storage device can provide a complete solution without any IT expertise or advanced knowledge. The HP StorageWorks Media Vault Pro mv2040 is an ideal solution for small businesses, because it combines data protection with simple file serving and secure offsite storage for a total answer to the problem of backup and recovery.³²

But why would you want to back up your system to tape anyway? It's true that only a few years ago hard disk storage cost ten or even twenty times the price of tape drive cartridges for comparable amounts of storage. But now you can buy a 750 MB SATA drive for around $300, and that means tape is now only about half the cost of disk storage.⁶⁴

There are two sizes of Zip disk available, 100 MB and 250 MB. A Zip drive that supports the 250 MB disk size will also support disks of the 100 MB size; 100 MB Zip drives support only 100 MB disks. While the 100 MB disks and Zip drives cost less, you should consider the possibility that some day your data may not fit on a 100 MB Zip disk.⁷³

The lowest level of disaster is a server crash of some sort. This has a very high likelihood of happening some time within a 5-10 year period. It can be either physical (the server dies) or inflicted from the outside, by a virus or disgruntled employee. Your goal in this case is to recover your data rapidly. The most common protection is a tape backup. However, there are several caveats you need to be aware of.⁷⁴

Disasters that affect entire sites or regions � including earthquakes, floods, hurricanes or extended power outages � can render traditional backup technologies useless, even if fault-tolerant devices are employed. Any disaster event that reaches beyond the single building level threatens to destroy not only the primary, operational system, but also the redundant hardware and its backup data. By maintaining a copy of mission-critical data on a target server geographically removed from the source server, network data mirroring eliminates the risk that a site- or region-wide disaster will damage both original and backup data and systems.⁴⁴

Did you get the implication about DVD's? One DVD-R/RW may be able to backup everything on your hard drive. DVD-RW's could be marked for each day week (Monday, Tuesday and so forth) and rotated.⁹²

Tape backup is also a nice option for backup because you are able to backup as much data as you choose without having to purchase additional hardware. All that is required is the purchase of additional tape cartridges to backup more and more data. If you were to back up your data on secondary hard drives, you would have to continually purchase new hard drives as the size of your data grows. Also, hard drives are subject to hardware failures that could render the data unrecoverable. Tape backup is a good option because with it, you're not reliant on any single piece of hardware. The data is stored on a backup tape that can be used in a different tape drive if necessary to restore your data.⁵⁵

Fibre Channel SANs encompass the connection between storage and servers, as seen in Figure1. SANs service a limited number of servers that distribute data to a large number of users over an Internet Protocol (IP) network such as Ethernet. The close-knit Fibre Channel network, known as a fabric, is optimized for large data transfers with low overhead, low-latency switching, and minimal interruptions to the flow of data. A typical user would not have a direct connection to the SAN but would access the data stored in the SAN via a server on the IP network. Fibre Channel increases the performance of data transfers to levels that are unmatched by any other technology.⁸⁷

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Data can be moved from one storage device to another to optimize configurations. As Figure3 shows, reconfiguring data can free up entire storage devices for other applications. Storage in SANs is independent of servers, so it can be logically consolidated yet remain physically separated.⁸⁷