Maintaining your computer isn't an optionit's a requirement if you want to get optimal performance and value from any machine. A lot of my clients used to have a problem with this statement. After all, what could go wrong with a solid state device? Wasting time and effort cleaning the inside of a PC seemed ludicrous to many of them. Then, I started adding up the cost of every service call I made and showed how they could have saved that money by spending a little time in maintenance. This piqued their interest enough to add other costs in as well, like employee down time and cost of lost data. It didn't take long for them to figure out that it cost less to maintain a machine than to call me out every few weeks to fix it.
The first thing that comes to mind when I mention maintenance to most people is cleaning and general repair, such as looking for frayed wiring or listening for a bad fan motor. Sure, these items are a part of maintenance: A well cleaned machine will run significantly longer than one filled with dust balls. Cleaning your floppy, tape, and optical drives only makes sense; dirty drives have problems reading the media you're depending on to store data.
Obviously, cleaning and general repair aren't the only maintenance items you need to think about. I previously mentioned the cost of data; a lot of these people didn't back up their employees' workstations because they didn't contain any data. (I've run into more than a few cases where an employee stored personal data on his local drive instead of placing it on the network. The network administrator is usually the last to know about such "secret" data caches.) Trying to completely reconstruct a workstation can take a day or even more. Even if a workstation doesn't contain data, just backing up its configuration can save an administrator precious hours of installation time.
I covered a lot of different diagnostic programs in the preceding chapter. Running diagnostics from time to time is also one way of detecting problems with your machine early. A diagnostic designed to detect hardware problems can usually detect them long before you'll actually see a problem. Contrary to common belief, a hard disk doesn't just decide to become hostile and break itself one morning (although this would probably happen if you dropped the machine). You can usually see drive errors start to crop up a few weeks before the drive actually fails. A diagnostic program can usually detect some of these errors. The same holds true with power supplies. The two diagnostic cards from Landmark I mentioned in the preceding chapter also have a power supply tester included with them. You can plug in the card and determine whether your power supply is up to par. By the way, a power supply that starts producing less than the required level of voltage for your machine reduces its life span by introducing an undervoltage condition.
If you haven't figured it out yet, we're going to spend some time talking about the maintenance aids Windows NT provides. I wouldn't consider these the cream of the crop, but they do the job well enough for a single workstation. We'll look at backup first. I consider this one of the least used maintenance options on networks today despite the advances made in tape backup systems. I'll also spend some time looking at some Windows NT-specific diagnostic and maintenance aids for your hard drive.
Backing up your data is an exercise everyone hates to do. It always seems to take a long time and wastes perfectly good hours you could use for some other purpose. Of course, the day will come when your system will take a nose dive (usually after you've decided that backing up takes too much time) and you really will need that backup. Making a backup of your system is like buying insurance: No one ever sees a good reason to do it until disaster strikes, and then it's too late to do anything if you didn't prepare in advance.
Some people will try to make a backup of their system using floppy disks. That might have worked in the days of 33MB hard drives, but with today's 1GB and higher systems, it just won't work. Even if you did have the time required to create a backup with all those floppy disks, it just isn't practical from a variety of other vantage points. Just imagine the joy of trying to find the one file you need to restore from a stack of floppy disks, for example. Of course, that assumes that all those floppy disks remain in prime condition long enough for you to use them. It doesn't take too long to figure out that the age of floppy disks is long past. If you're going to back up your system, you need to invest in a tape drive of some type.
Unlike Windows 95, Windows NT provides a wealth of backup hardware options for you. You can select from a range of inexpensive solutions, such as a QIC-40/QIC-80 (quarter-inch cassette) floppy tape drive, to something designed for heavier loads, such as a DAT (digital audio tape) drive. The decision of which type of hardware to get isn't limited by the operating system in this case. (I always considered the lack of hardware support under Windows 95 a bad decision on the part of some marketer trying to make an artificial distinction between it and Windows NT.)
There are some rules of thumb when it comes to tape backup systems:
Note: I won't cover the process of performing a floppy disk backup in this chapter for two reasons. First, a floppy disk backup really isn't all that practical except for the very smallest backup sessions. Second, the procedure for a floppy disk backup is so similar to the tape backup that you won't experience any problems going from one to the other.
Before you can use the Backup utility, you'll need to install a tape drive. To do this, open the Control Panel and double-click the Tape Devices applet. Select the Drivers page and click the Add button. You'll see a dialog box similar to the one shown in Figure 26.1. This is where you'll select the tape driver you want to use. Notice that the screen includes a Have Disk button. Click this button if you want to use a vendor-supplied driver in place of one of the Microsoft-supplied defaults.
Figure 26.1. The first step in adding a tape drive to your system is to install the driver.
After you select a driver, click OK. At this point, Windows NT loads the required software and then attempts to start the driver. In most cases, it'll start the driver and you'll be able to use the Backup utility immediately. However, some drivers, especially those connected to the floppy system, require you to shut down and restart the system. You'll get some ambiguous message from Windows NT stating that it didn't have enough resources to start the driver. Ignore the message until you try to start the driver by restarting the system. If the driver won't start after you reboot, there might be a real problem that you'll have to check before you can get Windows NT to recognize the hardware. You can always check the status of your tape drive by looking at the Devices page of the Tape Devices dialog box (see Figure 26.2). The page will show which driver is loaded. You should also check the Drivers page to make sure that the driver is started.
Figure 26.2. The Devices page of the Tape Devices dialog box tells you which tape drive device driver you have loaded.
Now it's time to start the Backup utility. Just select it from the Administrative Tools folder on your machine. The status bar shows that Backup is initializing the tape drive. If there's a tape in the drive, Backup attempts to read it. After Backup gets everything started, you end up at the Backup window shown in Figure 26.3. It contains two main buttons: Backup and Restore. The other six buttons allow you to perform various operations: Catalog, Retension, Eject, Erase, Check Highlighted Items, and Uncheck Highlighted Items.
Figure 26.3. The Backup utility provides all the tools you'll need to create backups under Windows NT.
Note: Windows NT may require you to erase or reformat a tape if you use preformatted tapes. You'll see a message box telling you to perform the required action. In most cases, the erase message will appear if you previously made a backup on the tape using something other than the Backup utility.
Tip: You can always tell if the hardware detection was successful by the status of the Operations menu. If you see that all the tools are available, Backup successfully detected your drive. Make sure that you perform the detection with a tape installed. Backup can't detect some tape drives correctly if the tape isn't in place.
At this point, you should have a tape drive installed and a tape in place. Format the tape, if necessary. I always use preformatted tapes because it takes such a long time to format some of the larger tapes you'll find on the market today. Now you're ready to perform either of the two actions outlined in the following sections: backup or restore. (Unlike the Windows 95 Backup utility, the Windows NT Backup utility doesn't provide a separate Compare feature.)
The first activity you'll perform with Backup is creating your first backup tape. You'll need to select entire drives or specific folders/files on the drive. Double-clicking on a drive displays its contents. Figure 26.4 shows the initial Backup window with a drive open. As you can see, boxes appear next to each drive and folder on the left side of the display and next to each folder and file on the right side of the page (the interface works much like Explorer, where the right pane shows a detailed view of whatever you select in the left pane). You select the items you want to back up by clicking on the boxes. An empty box means that Backup won't send that item to tape. A gray box with a checkmark appears next to a folder or drive that you intend to partially back up. A checkmark appears next to a file, folder, or drive that you intend to completely back up.
Figure 26.4. The initial Backup dialog box allows you to select the files you want to store on tape.
Tip: The first time you back up your system, Backup might find some files it can't verify. Always check the ERROR.LOG file in the \WINNT folder. This file tells you which files Backup couldn't verify. In most cases, you'll want to exclude these files unless you have a good reason to keep them in the backup set. I've found that most of these files end up being system-specificfiles I would normally need to install manually before a restore.
After you complete the selection process, it's time to select a target for the backup. Most of you can skip this step because you'll only have one backup device available. Windows NT automatically selects a device if you only have one available. You should see a minimized Tapes window at the bottom of the Backup window. Just double-click on it to see which devices are available. Figure 26.5 shows a typical selection window. As you can see, Backup allows you to select any tape as a storage location.
Figure 26.5. You use this window to select the backup target. You also use it to save the backup set.
Click Backup to begin the actual backup process. You'll see a dialog box similar to the one shown in Figure 26.6. You'll have to provide several important pieces of information here before you proceed with the backup.
Figure 26.6. You use the Backup Information dialog box to define the backup characteristics.
One of the first things you'll need to decide is what to call the tape. I normally use the default setting shown in Figure 26.6 unless I make more than one backup in a day. In that case, I usually add just enough information to differentiate the two backup tapes.
Four configuration checkboxes appear right below the Tape Name field. Always check the Verify After Backup checkbox. Sure, it takes a little time to verify the backup. All an unverified backup gives you, however, is a false sense of security. If you're making any kind of a daily backup, you'll want to enable the Backup Registry checkbox. I consider the registry one of the most important pieces of information on my system. Just think: Without a registry, you can't even get Windows NT to boot properly. Suffice it to say that you won't want to miss an opportunity to preserve your configuration data. You can restrict access to a backup by enabling the Restrict Access to Owner or Administrator checkbox. About the only reason I can think of to do this is if the backup contains sensitive data. Normally, you'll still want to give access to the data to your backup operatorsthe only people who can restore data using the default security setup. The fourth checkbox, Hardware Compression, is only available to tape drives that support it. Normally, I select this option when it is available, because hardware compression takes part of the processing load off the workstation and hands it off to the tape drive.
To the right of the configuration options is an Operation group box. It contains two options: Replace and Append. If a tape already contains a backup, you can choose whether you want to replace the current backup or append a new backup to the tape. Obviously, this option is enabled only when you store more than one backup to a tape.
A backup set is one complete backup on a tape. You have to tell Backup how to perform the backup and what you want to call it. That's what the entries in the Backup Set Information group are all about. You need to enter a description of the backup set to start with. I normally choose something short but descriptive. Typing Today's Backup might seem descriptive at the time, but it hardly tells you anything when you go to restore the tape. You also need to select a backup method in the Backup Type drop-down listbox.
The backup types Windows NT supports Follow:
The last group in the Backup Information dialog box allows you to change the way Backup logs events during the backup cycle and where it logs them. I normally keep the backup log options set to the default. The amount of information I place in the log depends on the situation. If I'm encountering problems with the tape drive, for example, I'll probably select the Full Detail option. On the other hand, the Don't Log option comes in handy for quick backups that don't affect the overall backup strategy. Normally, you'll want to retain the Summary Only option that Backup uses as a default.
Now that you've finished your backup configuration, it's time to start the actual backup process. Just click OK to start the backup process. You'll see a Backup Status dialog box like the one shown in Figure 26.7. Notice that the dialog box provides a summary of the Backup utility's actions as well as the number of files and directories it has backed up. After the backup completes, you'll see a message like The operation was successfully completed in the Summary listbox of the Backup Status dialog box. Click OK to exit the Backup Status dialog box. At this point, you can exit the Backup utility if you don't have any other data to back up.
Figure 26.7. The Backup Status dialog box tells you how the current backup is progressing.
Note: The title of the Backup Status dialog box may change during the backup process to reflect the current operation. During the Compare part of the process, for example, the title changes to Verify Status. The dialog box still contains the same informationonly the operation has changed.
Restoring a backup follows a process that reverses the one you used for creating the backup in the first place. You start by specifying the original target device and the backup set you want to use. In most cases, this will be a hard or a tape drive. Then select the files from that backup set you want to restore. Finally, you start the Restore process.
You'll want to select the Tapes window to start the process. You'll see one or more tape drives containing one or more backup sets, as shown in Figure 26.8. There are several ways to select the data you want to restore. If you placed your full and incremental backups for a given week on one tape, you could simply select the tape to completely restore your data to its last backup state, for example. Of course, you can select a specific backup set to restore just a portion of the data contained on the tape. I use this option when I want to restore one of the partial backups I made during the day. You can also double-click on a particular backup set to see what it contains. This allows you to use an Explorer-like interface to select specific files to restore. Obviously, the method you choose depends on what you eventually intend to get out of the restore session.
Figure 26.8. Restoring data begins with the Tapes window.
After you select the data you want to restore, click the Restore button in the Backup window. You'll see the Restore Information dialog box shown in Figure 26.9. Notice that this dialog box contains several different areas that allow you to control the way Backup restores the data to disk.
Figure 26.9. The Restore Information dialog box allows you to control how Backup restores data to a drive.
The Restore group controls where the data gets restored. Backup always defaults to the backup directory. You can use the Restore to Drive drop-down listbox to restore the data to a different drive. The Alternate Path field allows you to change the folder used to hold the data. Below these two fields are two checkboxes. Check the Restore Local Registry checkbox if you want to restore any registry data contained on the tape. I use this option for a full restore but keep it unchecked most of the time. You don't want to restore your registry information unless it's damaged in some way. The current registry information will get overwritten if you do. I always enable the Restore File Permissions checkbox. This checkbox tells Backup to restore the security information to its backed-up state. Because security setups can get quite complex, letting Backup do most (or even all) the work for you only makes sense. The only time I omit this option is if the tape's file permission information is radically different from the current setup.
If you look below the Restore group, you'll see the Verify After Restore checkbox. I always enable this checkbox. It costs you a little time, but I like to know up front whether any of the data on the tape is damaged. Checking this option can also let you know whether the restore went as planned. Sometimes, damage to the tape drive doesn't become apparent until you try to restore data.
As with the Backup Information dialog box, the Restore Information dialog box provides a method for logging events. I already covered these options, so I won't cover them again here.
After you finished setting up for the restore, click OK to start the process. You should see the Restore Status dialog box shown in Figure 26.10. It tells you the current number of files restored to the drive as well as any summary information. After the restore completes, you'll see a message like The operation was successfully completed in the Summary listbox of the Restore Status dialog box. Click OK to clear the Restore Status dialog box. At this point, you can exit the Backup utility if you don't have any other data to restore.
Figure 26.10. The Restore Status dialog box keeps you informed about the current status of the file restoration.
I'm almost never satisfied with the thin brochures tape vendors call manuals. A quick look inside usually provides one or perhaps two pages of installation instructions. If you're lucky, you'll also get a page or two of troubleshooting instructions. Because these rather short instructions leave too much to the imagination, I came up with a few time-tested techniques for getting the most out of your backup system.
The first step, of course, is to select some hardware and software. I go by three simple rules:
I always shop around for my tape drives, because the prices tend to vary a lot more than for common items such as memory. You never know when you'll get the super deal of a lifetime from one of the stores you frequent a little less often. After you do select the hardware and software you intend to use to back up your system, it's important to test it and maintain it. I really find it hard to believe that some people just throw the tape drive into their system and expect it to work. Testing ensures that the data you back up today will actually work when an emergency arises. Maintenance increases the longevity of the equipment you use.
It's important to take a two-phase approach to testing your new backup system: a full test today and a maintenance test tomorrow. After the initial equipment installation, you should completely test your system to make absolutely certain that it works. You need to test the hardware, software, automated procedures, macros, and anything else that might stop you from getting a good backup. Test your system in stages using the procedures contained in the following "Initial Installation" section. Make sure that you use techniques that fully test the hardware and software combination as well as the individual components.
After you get things up and running, you need to continue testing your system from time to time. This confirms that the software and hardware are still working. Remember that this is your life's work in data we're talking about here, so even a little failure is important. Some breakdowns aren't as obvious as smoking tapes or tape drives and remain undetected by the backup software.
I still remember one shop where I was called in as a consultant to solve a mystery. Someone at the shop installed a tape backup system and checked to make sure that it worked. After that, he performed a back up of his system every day. The backup software always told him that he had gotten a good backup, and he had no reason not to believe it. Eventually, he needed to use the backup he made to restore some data. To his horror, the preceding day's tape contained absolutely nothing. One by one, he checked every other tape he made; the network administrator discovered that these were blank as well. The culprit of this gruesome scene? The write head had fallen off inside the tape drive with the wires still connected. As a result, the tape drive never sensed that the head was dysfunctional. In fact, the tape head really worked just fine. The data it wrote simply didn't get onto the tape. Because the backup software didn't compare the contents of the tape to the contents of the drive after the backup, everything appeared to work fine. The moral of this story? You can become a casualty of hardware or software errors, or you can test your system. Hardware tests aren't a convenience; they're a necessity for people who want to get the most out of their systems.
Let's talk about another issue most people fail to consider: tape drive maintenance. Many network administrators delay their tape drive maintenance until it's too late. After all, who'll ever see the tape drive sitting in their office? It's much better to keep the print server, which the boss can see, clean. In the preceding example, the network administrator would've found the fallen write head if he had simply maintained his tape drive. Every drive on the market requires cleaning and physical head inspection. You can either use a cotton swab and alcohol (much like the maintenance you perform on your tape system at home), or you can use a specially designed tape cartridge to clean the drive. In addition, the vendor manual that comes with your tape drive should include some detailed maintenance procedures. (Most don't include complete instructions, so I've included the set I use in the following sections.)
I always perform a visual check of any equipment I buy before I install it. The more pieces I have to install, the closer I look before I begin. You can use the same procedure I do to make sure that you get the best installation possible. First, if the vendor supplies a checklist or picture of the equipment, use it to make sure that you have everything. It's not unheard of to get a package that doesn't contain everything you need. Perform the same check for your software. Make sure that you have the right licenses and that the disks aren't corrupted. Also perform a virus check on any disks. Check your tape supply and make sure that you have enough on hand to perform a full backup cycle. (We'll talk about this topic in the next section.) After you have all the components required to install your tape drive, it's time to do the actual work.
Now that you've gotten the easy part out of the way, it's time to start a staged installation/test of your system. What exactly is this process? It begins with a test of the base installation and then tests each addition you make to it. As a result, you spend a lot less time troubleshooting installation problems, and you know exactly where weak areas in the system might occur. The following paragraphs provide you with six easy steps you can follow to get a great tape drive installation. These are generic instructions, so you'll need to make some modifications to this procedure to reflect your hardware and software setup. Some companies also have a set of policies in place. Make sure that you follow any company-specific regulations as well.
This six-step procedure should help you get up and running quickly. The most time-consuming part of the process should be writing and testing the macros required by your backup system. In most cases, you should be able to get a tape drive installed and running in less than a day. Of course, it's always a good idea to prepare for the worst, just in case it happens.
Every piece of equipment on the network requires maintenance, and the tape drive is no exception. Maintenance includes both cleaning and physical examination. It might include replacing filters and belts as well. Your vendor manual should include a set of procedures for maintaining your tape drive. Remarkably, some vendor manuals don't include these vital instructions. Somewhere along the way, a few vendors got the idea that they should sell maintenance instructions as a separate item. You might want to give your vendor a call, just to make sure that your equipment doesn't fall into this category. If you can't seem to find any vendor instructions, feel free to use the same set I do for generic tape drive maintenance. Make sure that you have a flashlight, cotton swabs (the type used to clean tape drives), methyl or isopropyl alcohol, and any required filters.
To perform tape drive maintenance, follow these steps:
I find that maintaining the tape drive attached to my system is a lot easier than the alternative. Never buy faulty insurance. A tape drive that isn't maintained is worse than no tape backup at all. At least if you don't have a tape backup, you won't have any unexpected surprises when a hard drive fails. A good tape drive is like good insurance: It's always there when you need it. It's a good idea to perform this maintenance at least once every three months unless the vendor specifies a different maintenance cycle. You might want to perform maintenance more often if the tape drive is in a dirty or hazardous area.
You might want to take this opportunity to check your tapes as well. Tapes get old and wear out just like anything else on your system. You can use three quick steps to check a tape. First, look for any physical damage, such as a cracked case. Damage of this type might damage the tape drive as well. Second, look at how the tape is wound on the spool (also known as the tape pack). Does it appear wavy instead of smooth? Can you see individual wraps sticking above the level of the other wraps on the spool? If so, try to re-tension the tape. If this doesn't give the tape a smoother appearance, the tape might contain stretched areas. Finally, the maximum time you should use a tape is five years. If your tape is more than five years old, consider replacing it even if it looks good. You might want to consider replacing heavily used tapes more often. If you use a tape every day, you should consider replacing it every two years.
Tip: Some tape vendors suggest placing a label on the tape and making a hash mark every time you use it. After you reach 40 uses, discard the tape and use a new one. This might provide you with an added level of security if you store the tape in an overly warm or dry environment or in a dirty environment.
I actually walked into a business once with a state-of-the-art file server, up-to-date workstations, and a tape backup system to boot. The only problem was that they had only one tape. A one-tape shop will always run into problems. Even if you assume that every backup will work exactly as expected, several other things could go wrong. A fire could strike at any moment, for example. A one-tape shop would come in the next morning and find its tape safely stored in the safe where it always is. Of course, it would be a ball of melted plastic, but it would still be there. Floods and theft aren't out of the question either. A lot of things can happen to your data, and if you keep it all in one place, it takes only one accident to turn your business into a disaster. Hopefully, this makes my point about the need for rotating your tapes.
You can rotate tapes many ways. The technique you use depends on the requirements of your company, the value of your data, the types of applications you use, and the number of tapes you have on-hand. Every tape rotation method shares three things in common:
I usually use a three-tape strategy for small businesses. My own setup uses a six-tape strategy. The following paragraphs examine some common backup rotation techniques. Although none of these methods might exactly fit your needs, they do provide you with enough information to come up with a reliable rotation scheme of your own.
Tip: Tapes are cheap when compared to the cost of the data they hold. Buying a few more tapes might rescue your data from disaster. Never let the cost of the tapes you buy interfere with a good backup strategy.
This is the method I recommend to small businesses on a very tight budget, because it represents the very least you can get by with and still maintain a safe backup strategy. Use this method for less-complex installations that use the network primarily for word processing and small spreadsheet files. This technique usually meets the needs of a small four- or five-person company that doesn't use a complex accounting package or rely on a database management system. You might not want to use it for applications that rely heavily on shared files. The reliability of this technique greatly diminishes as the number of files you want to protect increases. Figure 26.12 illustrates this technique.
Figure 26.12. The three-tape, full backup technique works well for small businesses.
The nice thing about this tape storage method is that you still maintain an off-site storage capability. This method easily expands to four, five, or even six tapes. Because the tapes do rotate at a fairly high rate, you'll need to replace them more often.
This technique uses one dedicated tape for each day of the work week, reducing the probability of virus infection or other damage that can occur when you use one tape for both full and incremental backups. Monday and Friday are full backup days, whereas Tuesday through Thursday require only incremental backups. The Friday tape alternates between the off-site storage site and on-site storage. Use this technique for moderately complex setups that rely mainly on word processing and spreadsheet applications in a nonshared environment. You can also use this technique for installations with small accounting systems or moderately complex database management systems. Figure 26.13 illustrates this technique.
Figure 26.13. This six-tape method works well for moderately complex setups.
The advantage to using this system is that it's more reliable than the three-tape system, yet it requires less maintenance time than creating full backups each day of the week. The only disadvantage of this system is that the Monday backup represents a weak link in the backup chain. If the Monday backup becomes corrupted, the incremental backups you make from Tuesday through Thursday also become worthless. You could conceivably lose four days of work by using this method. Of course, this assumes that a network crash occurs on Thursday afternoon or Friday and that you have a corrupted Monday backup. Although this sequence of events is unlikely, it could happen.
One way to expand this particular backup technique is to add additional Friday tapes to the sequence. You could easily make this a nine-tape sequence, for example, which would allow one Friday tape for each week of the month. Expandability is one of the things I try to keep in mind when setting up a tape-rotation scheme. It's always easy to use fewer tapesfinding a good way to use more can get to be a challenge.
I find that this particular rotation scheme works best with medium-size businesses that have very robust data storage needs (see Figure 26.14). If you rely heavily on a data entry or an order entry system, for example, this is the rotation scheme you need to look at. This technique uses one dedicated tape for each day of the week. The Friday tape alternates between the off-site storage site and on-site storage.
Figure 26.14. This six-tape method works well for moderately complex setups that rely on data entry systems.
This rotation scheme overcomes the weakness of the six-tape full/incremental rotation described in the preceding section by using a full backup each day of the week. Of course, this means that maintenance time increases in proportion to the total size of your network rather than the size of the files you change each day. On larger networks, it might also mean an increase in the total number of tapes if you need more than one tape to make a full backup of the network. Unfortunately, your tapes will wear out faster because they'll receive a higher level of use with this method.
The best way to expand this rotation scheme is to double the number of tapes so that you alternate sets between odd and even weeks. This will improve security and reduce tape wear. It also allows you to maintain more tapes off-site, further reducing the chance that one tape failure would prove disastrous.
Large businesses require a more complex rotation scheme to ensure that their data remains safe. Not only is it unlikely that you'll use a single application or perhaps a simple group of applicationsit's very unlikely the network administrator will have as firm a grip on the inner workings of the company. (Not that the administrator is incompetent, but administering a large setup leaves little time to understand how everyone else uses the computer.) The larger and more complex your network, the more desirable it is to provide several stages of network backup.
Added to these other complexities are the problems of local storage. It's improbable that all your data will appear on the network; managers will probably keep some of it on their local hard drives. Proposals and other sensitive information are likely candidates for local storage. Unfortunately, the manager could lose that data during an emergency unless you back it up. The 14-tape, full backup technique combines the best features of the six-tape method with workstation backup. Figure 26.15 illustrates this technique.
Figure 26.15. The 14-tape rotation scheme adds workstation backup to the mix of features.
As you can see, this technique provides one backup per week for all workstations on the network along with one tape per week for file server off-site storage. You could further expand the backup scenario to make daily full or incremental backups of the workstations. In most cases, however, you should find the Friday workstation backup sufficient.
You can look at this backup method in two distinct ways. The first way is a four- or five-tape rotation. Instead of looking at tape backup on a monthly basis, you simply keep the Friday backup and workstation backup tapes in constant rotation. To implement this strategy, simply mark a calendar with the numbers 1 through 5 (or 1 through 4) on each Friday of the year. The first Friday you use tape 1, the second tape 2, and so on. On the sixth Friday of the year, you start over with tape 1. Of the two methods, this is the simplest way to implement a 14-tape strategy.
The second way to look at this backup method keeps the needs of accounting firms and other month-oriented organizations in mind. Some applications perform special processing at the end of the month and the end of the quarter. They summarize the preceding month's data and then get rid of the information used to create the summary. Making a backup before you do this processing ensures that you keep the old data if a problem occurs during processing but doesn't become apparent until sometime later. To implement this method, always use Friday and Workstation tape 1 on the first Friday of the month. Similarly, use tape 2 on the second Friday of the month. Using five tapes ensures that you have enough tapes for months with five Fridays.
You should never consider off-site storage as an option. It is a mandatory part of the backup process. Disasters strike when and where you least expect them. An unexpected electrical fire could totally wipe out your company tomorrow. Floods, earthquakes, tornadoes, broken pipes, and other disasters can strike at any moment.
Protecting your company's data is the main reason to create a backup. It's unlikely that a disaster will annihilate two places simultaneously, especially if those places are some distance apart. Placing your data in more than one location helps reduce the probability of tape destruction by a disaster.
Two types of off-site storage are available. The more expensive solution is to use the services of a company that specializes in providing off-site storage. These companies usually provide a fireproof vault for storage purposes. It's very unlikely that tapes stored in such a facility will get damaged in the event of an emergency. Besides the cost factor, you'll want to examine the types of service offered by the company. Some companies offer 24-hour service, but this costs significantly more than those who offer daytime-only service. Although you might save money using the latter, it's also unlikely that you could retrieve a tape on the weekend or after working hours when using this type of service. In some cases, this might prove inconvenient, but it shouldn't sway you from using these services.
The second solution is to select one or two people from management to use their homes as off-site storage sites. Make sure that you get the approval of management to do this. Unless management really trusts this person, you could end up handing company secrets to someone who might try to sell them elsewhere. When using this technique, the person stores the tape at home and brings it in when it's time to replace it on-site. Although this form of off-site storage is less secure than using a professional service, it is a lot less expensive. The down side to using this method is that the same disaster that destroys the on-site tape could destroy the off-site tape as well. The off-site tapes are also subject to theft and vandalism. Of course, one advantage of using this technique is that you'll have a good chance of retrieving a tape on the weekend or after hours.
You can also combine both techniques. Storing one tape in a vault and another at a manager's house will provide you with the advantages of both systems. In addition, you reduce at least one of the problems with using either technique alone. By storing one tape in a vault, you no longer need to worry about the same disaster destroying a tape in both the on-site and off-site storage locations. In addition, you can count on reaching the manager after hours or on the weekend to retrieve a backup tape.
Write your own tape-rotation plan based on the examples in this chapter. Make sure that you weigh the cost of the time involved in creating the backup versus the cost of replacing lost data after a system crash. Also add times to the schedule for replacing your tapes. Don't let an old tape lull you into a false sense of security.