20 May 2006

Introduction

A Harris Poll of senior executives in Fortune 1000 firms this summer found:

After the wake-up call of 9/11, one-third of executives admitted their companies were still no more prepared than they were that day.
Also, 40 percent of the executives fear that only a handful of their employees (less than 10 percent) even know what to do to recover data and get their businesses running again in the event of a catastrophe.
One in three companies are operating today without a formal disaster recovery plan.
Almost two-thirds (64 percent) of the companies surveyed also admitted that their data backup and disaster recovery plans have “significant vulnerabilities,” according to the poll.
One third of the companies with a formal plan reported they don’t test it regularly, and two-thirds said they do not conduct regular external audits of their data storage and backup systems either.

Yikes, if that’s the scenario in big businesses with lots of resources and staff, what do you suppose is happening in small and SOHO businesses?

Why Backup Your Data?

Why should you backup the information on your computer? Unless you are willing to sacrifice the information contained on your computer, you must plan for the worst. Computer equipment, including disk drives, fails. Backups are like insurance. You may never need it, but if disaster strikes, you will thank your lucky stars that you had something on which to fall back. Last month we published an article entitled “What is Your Company’s M.A.D. Time?” which defined the term “maximum allowable down time” of your systems. Unless you have backups, your minimum downtime is the time it would require to compile and re-enter all the programs and data on your computer. In this day and age, that could take days and even weeks and, most likely, cannot even be achieved. Hard disks, which contain all the information stored on your computer, fail. It is a fact of life. Hard disks last longer than ever before, but they do fail eventually – and usually unpredictably. Hackers, computer viruses and worms and spyware destroy data. Your best defense against loss of data is to backup your data on a regular and systematic basis.
In this article, we discuss the why, what, where and how of performing data backups. Several approaches and solutions are presented. Your specific solution must take into account your M.A.D.

What Is a Backup?

A backup is a copy of the data and/or programs on your computer. Backups are best accomplished using a software package specifically made for backing up information onto external media such as magnetic tape, CD-Rs, DVDs, etc.). With some backup systems, you can back up all the data and programs contained on your hard disk. Some systems allow you to do “incremental” backups. This means that you back up only the files that have changed since the last time you backed up these files.

If the backup system saves everything from your hard drive to an external medium (like tape) and subsequently your hard drive fails, you will only have to restore the data to a new drive (after reloading the operating system and backup/restore software) in order to recover from the disaster of the hard drive failure. A properly and thoroughly prepared complete system backup can restore everything for you. If you have used only incremental backups, however, you must restore your most recent complete backup and then sequentially install each incremental backup to restore all of the data to its most current state.

It is common for backups to be made by saving one complete file at a time. These are called file-by-file backups, and it doesn’t matter where on the hard disk the files are physically located. The backup will start at the beginning of one file and copy it to the end of the file. Then it will start with the next file on the list. With this system, each file backed-up can be restored. This type of backup should not be used to restore programs or system settings because programs and system settings require interaction with each other.

What Are The Types of Backup Media?

There are several types of backup media, but the most common is magnetic tape such as digital audiotape (DAT), digital linear tape (DLT), and Travan tape. Of the three, the DAT and Travan media are the newer technologies. They are less expensive but a little slower than DLT. Digital audiotape would be a good media to use to back up data for most small businesses. A DLT backup is more appropriate for larger operations and Travan is a good in-between media selection. Other backup media are Jazz drives, Zip drives, CDs, and writable DVDs.

How Many Tapes or Media Should I Use?

There are many strategies for backup tape rotation. These include the grandfather-father- son strategy, the Tower of Hanoi strategy and the incremental tape strategy. The method and strategy used in rotating tapes should reflect the critical nature of the data to be backed up and the potential for losing a tape in the sequence. For most businesses, either the three-tape backup, the six-tape backup, or the ten-tape backup offer increasing degrees of security, based on the number of tapes, without overly complicated rotation schedules.

For an excellent summary of tape backups and examples of three, six, and ten-tape backup plans, visit this site.

What is A Remote Backup?

Another method of backing up your system and data involves off-site (remote) storage systems/servers in conjunction with software running on your computer(s) that automatically schedules, encrypts (for security), and transmits the data to the remote site. This type of solution accomplishes two important goals of backup – the offsite copy provides for data redundancy and offers security in case of fire or other catastrophic disaster at the business location being backed up. Most off-site backup storage solutions are subscription based.

Duration of storage, maximum daily and monthly data transmission and storage are all factors that influence the cost and effectiveness of this solution. Prices may range from tens of dollars per month to hundreds of dollars per month. Because a third party backup service will be storing your data, confidentiality of information also need to factor into consideration of an off-site remote backup solution. It is best if the data is encrypted at the origination point, before transmission to the storage site. If recovery of data becomes necessary, then decryption of data should occur at the data destination (recovery site).

What is Data/Disk Redundancy?

One form of redundancy is a disk drive array. It might be rated at 99.9% effective. This array is usually referred to as a RAID system, which stands for redundant array of independent disks. Two or more disks are controlled by a single or multiple disk drive controller cards. These cards cause the same data to be written to more than one disk.

One type of RAID increases speed by causing snippets of data to be written across multiple disks. These disks work simultaneously to grab all data you need very quickly. Another type of RAID duplicates all data from one disk to another. If one disk drive quits working properly, the duplicate data on the other disk are automatically used. The nonworking disk can be replaced with minimal downtime and no lost data. There are several types of RAID solutions with, as one might expect, different pros, cons and costs.

How are Data Backups and Disaster Recovery Related?

Disaster recovery is a much broader subject than data backup. It involves all aspects of preventing a disaster and being able to quickly recover from one should that be necessary. Disaster recovery is preparing for the worst. Since September 11, 2001, more people have paid attention to disaster recovery. Although terrorism is uncommon in the United States and practices are rarely damaged by fire and water, you should take simple steps to prepare for a catastrophe. In middle Tennessee, some of our greatest natural enemies are tornados. If you live in an area frequently affected by tornados or other structure damaging natural phenomena, you should be sure you maintain a proper disaster recovery plan.

One simple step is to take your backup media off site every day or at least weekly. Minimally, each Friday evening, a designated staff member should take the backup media home.

If some catastrophe event were to happen, a backup that is one week old or less would be available. It wouldn’t have been destroyed by fire or water. One could argue that with a week-old backup, too much data would have to be reentered. However, if the office is destroyed and your computer data is only one week old, then in the grand scheme of things your practice is in good shape. Again, the key consideration in all aspects of backup planning is: what is your maximum allowable downtime before your business begins to fail?

If a staff member does take home backup media, he or she should be careful with it. Magnetic media can be destroyed if left in hot cars, on top of microwave ovens or near some telephones, for example, and data backup media should be taken to and stored in a fairly clean and dust-free, climate-controlled environment, preferably in the media storage case or cassette box that it came in when purchased.

How Frequently Should Data Backups Be Performed?

That depends on your M.A.D! However, we generally advise that backups be performed after each day the system is used. If your business has Saturday hours, you should do a backup on Saturdays. Ideally, your business should keep generations of backups. Consider keeping at least two weeks of daily backup media. Let’s say you have two weeks worth of backups labeled Monday 1, Monday 2, Tuesday 1, Tuesday 2, and so on. On this Monday, use the Monday 1 backup. Use the Tuesday 1 tape the next day, then Wednesday 1, and so on. The following Monday, start with Monday 2, then Tuesday 2, Wednesday 2, and so on. When the next Monday rolls around, choose Monday 1 again - This way, if the backups aren’t working properly for a while or if data has been lost but no one notices for a long time, you are covered.

We recommend that clients archive one backup tape offsite each month. Save it and do not reuse it. Replace it with new backup media. By doing this, you accomplish two important goals. First, you replace your backup media systematically so it doesn’t wear out. Second, you have saved yet another generation of your backups so that you can go back to it if you don’t discover for a long time that some data are missing.

What If I Don’t Back Up Regularly?

If you don’t back up your computer system regularly, you are playing Russian roulette with your data and possibly your business. Eventually, all computer hard drives fail. Lightening may strike and power outages can occur, which can corrupt data. Staff members have been known to trip over and unplug the electrical cable that supplies power to computers and servers. Sometimes staff members press the reset button instead of shutting down the computer properly. If any one of these things occurs, you may need your backup (i.e., your insurance). If you don’t have a recent backup, you and your staff will spend days, weeks, or even months trying to re-create your data.

Is It Important to Test Backups?

You bet! What is actually important is testing your ability to restore your data. The frequency with which you should test your restore capability is a function of your M.A.D. If the backup mechanism malfunctions in a certain way, it may report that the backups are being written properly when they aren’t. This occurs infrequently but is something worth checking.

For example, a tape drive may only be writing on one track. Instead of filling one track with data and then writing the next part of the data on the next track, the next part of the data are written on top of the first part. When the backup is “complete,” only the last section of data is on the tape, making it worthless.

Some backup software tests the data by verification, meaning the software compares what is on the tape to what is on the hard disk. Your vendor might offer to load one of your backups onto another computer to ensure the data are being written properly on the backup media.

Summary and Recommendations

First, think about and determine your (M.A.D.). M.A.D. is Maximum Allowable Downtime. Do not skip this step; I guarantee you will make sub-optimal decisions about your solution.

Second, develop a data backup plan. Backing up everything on your computer takes time and space but makes it easy to recover if the hard disk fails or something else causes catastrophic hardware failure. On the other hand, programs and operating systems can be reinstalled if you have the original installation disks. It is the data and settings that change most often. You can reduce the time and space necessary to backup if you only backup data or settings when they change. That takes planning.

Third, schedule regular backups. Most backup programs have the ability to create and execute scheduled backups. Unattended scheduled backups will require that all necessary media is pre-loaded onto the computer. If you need to backup more than the capacity of your regular medium (tape, cd, or other), then you will not be able to complete an unattended backup.

Fourth, plan to replace backup media. Magnetic tape media wears out. If you are using a tape once a week, you should plan to replace it at least once every two years.

Fifth, make sure the backups are actually working. Most backup programs create a log file during and after scheduled backups. Check these log files periodically to ensure that backups are being created and verified correctly.

Finally, test your ability to restore files often. An untested backup plan is not a plan! Make a backup of a single small data folder containing some non-critical data files and restore it, first to an alternate location, and then to its original location. Examine the restored files and compare their results. They should be identical.

If you need assistance in setting up your backup plan or implementing it, please contact us at info@backupreview.info with your requirements.