Data Centers

Choosing a system backup device

Do you fear the backup? Since the days of MS-DOS, safeguarding your data has had a reputation for tedium. In this Daily Feature, Faithe Wempen outlines how to choose backup media to make backing up your system less of a chore.


If you have been putting off your backups because you dread dealing with all that hassle, let me assure you that setting up a simple, reliable backup procedure that won’t be difficult to follow regularly is now a much more manageable task than it used to be. In this Daily Feature, I’ll outline some of the different kinds of personal backup hardware you can choose from so you can find the solution that best fits your needs.

How much data?
The key to picking the best backup device is to determine how much data you need to back up on a regular basis. Then, pick the lowest-cost, highest-performance backup device that can store that amount of data on a single tape or disc, and do it within an acceptable amount of time. It sounds pretty simple, but the wide array of choices can make the decision difficult.

Although most backup programs let you span several disks or tapes with a single backup set, you want to avoid having to do this because it’s inconvenient. With this type of backup program, you must be there to change the tape or disc at the right time, so you’re tied to the PC for the duration of the backup (which can take four hours or more). You don’t have to sit there every minute, but you do need to keep checking on the PC to see how the backup is progressing and whether a new tape or disk will be needed soon. This kind of inconvenience fosters the backup procrastination that so often spells disaster.

The simplest backup to perform is a whole-system backup that includes everything on your hard disk(s). That kind of multigigabyte backup will almost certainly take up more than one disk. Multigigabyte backup tape devices are available, although devices with a capacity of over 8 GB can be very expensive.
Note: When choosing a backup device, plan for the fact that you will likely have more data to back up in the future than you currently do. A safe estimate is to double your current need when planning for future expansion.
You might choose instead to do a selective backup—to back up just your data and settings and skip everything that can be reinstalled later from a CD. If you go this route, almost any backup device will serve, because you probably have only a few hundred megabytes of this type of information to back up.

Picking a device category
There are two broad categories of backup devices to consider for personal use: disk and tape. Let’s review the advantages and disadvantages of each.

Tape drives are slower and less efficient than disk drives, both for reading and writing, and the drives themselves can be expensive. In addition, there are many different tape-drive standards, so finding the right tape drive for your needs at the right price can be a bewildering shopping experience. However, today’s tape-backup systems can write many gigabytes (from 8 GB to over 50 GB, depending on the tape drive technology) on a single cartridge, making tapes a good choice for those with a lot of data to back up regularly.

Disk drives are faster and quieter than tape drives, and you might already have a usable drive in your system. CD-RW drives, extra hard disks, ZIP drives, Jaz drives, and LS-120 drives can all be used for backup. Except for hard disks, however, disk capacity cannot rival tape capacity; most removable disks can hold only 100 MB to 700 MB or so. That means that if you have a lot of data to back up, you will probably need more than one disk.

Tape backup has been a popular choice for decades, but some of the reasons that tape has been popular in the past no longer apply. In earlier days, hard disks were very expensive, and removable disks (like floppies) were limited in capacity to a single megabyte or so. Magnetic tape, in contrast, was relatively cheap, and the technology for reading and writing from tape was already mature and therefore inexpensive to manufacture.

Nowadays, however, disks are cheap enough that no one needs to disqualify them as a backup medium due to cost alone. A 30-GB hard disk costs less than a tape backup drive and a couple of tapes, so many people are simply buying an additional hard disk and setting up a mirrored drive for data security. (Windows 2000 makes this particularly easy.) In addition, removable disks like CD-RW, ZIP, Jaz, and LS-120 offer convenient storage of between 100 MB and 2 GB of data on disk.

Choosing a tape backup device
If you decide you need high-capacity backup (several gigabytes), tape is your best bet. There are dozens of standards for tape backup, but many of them are either obsolete or well on their way to obsolescence. Since we’re focusing on system, rather than enterprise-level, backup solutions, I’m purposely ignoring large-scale corporate backup solutions such as Digital Linear Tape (DLT) and 8-mm helical scan. These run into the thousands of dollars and hold more than 100 GB of data per cartridge.

The original type of quarter-inch tape backup was called Quarter-Inch Committee (QIC), and there were many different types, starting with the 60-MB QIC-02, introduced in 1983-84. Popular progeny of this standard included QIC-40 (aka DC-2000), which held between 40 and 60 MB, and QIC-80 (aka MC-2120), which held 125 MB. The last revision to this standard was QIC-3020XL, which could hold up to 680 MB. (These figures don’t include compression.) Then came the QIC-Wide standard, which used a wider tape to store more data. These ranged from 208 MB to 2.3 GB.

The current standard for low-cost tape backup systems is Travan. It is based on QIC technology, and some Travan drives can read certain types of old QIC tapes for backward compatibility. If backward compatibility is an issue, check the specs on the drive you are looking at to make sure your old tape format can be read. The TR-1 model holds up to 400 MB and can read QIC-40 and QIC-80 tapes, for example, while the TR-3 model holds 1.6 GB and can read QIC-80 and QIC-3020XL (among others). These two are entry-level drives that connect to a floppy controller or parallel port. Higher-end Travan drives, such as the Travan NS-20, can store up to 10 GB and use a SCSI-2 or EIDE interface.
The Tecmar (formerly Iomega) DittoMax is a proprietary tape backup unit that uses its own version of the Travan standard and holds between 5 GB and 10 GB. There are many other brands of proprietary drives, including Colorado and Conner.
Most tape backup systems can compress data as it is written, so you end up with approximately a 2-1 compression ratio on the average. (Data files tend to compress more than programs.) A tape drive that advertises itself as 4 GB/8 GB can hold 4 GB of uncompressed data or 8 GB of compressed data.

A new type of tape backup called OnStream ADR is gaining popularity. It uses a multitrack recording mechanism to record eight tracks at once, so it’s faster than most other tape backup devices. It’s also quieter; the tape moves at a slower speed through the drive since there are eight tracks to be written in a single spot instead of only one. It also features a variable-speed motor that allows the drive to compensate for hard disk read-time fluctuations.

How much money are we actually talking about here? If you’re shopping for a very cheap tape backup, one popular choice is the HP/Colorado 8 GB. It holds 4 GB/8 GB and costs around $200 to $300, depending on the model and interface. (External devices cost more.) Seagate also makes a comparable model that holds 10 GB/20 GB for around $300. From there, the prices go up pretty quickly into the $1000 to $3000 range for 33/66 GB and larger capacity.

Choosing a disk backup device
The problem with tape backup drives is that they’re basically one-trick ponies. Not everyone wants to sink $200 or more into a device that will take up a drive bay (or space on the desk) and can’t be used for anything except backup.

If you don’t have multiple gigabytes of data to back up regularly and you want a backup device that can also be used for normal storage, consider disk backup instead. There are many choices for disk backup. Here’s a quick list, from smallest to largest capacity:
  • ZIP: These range from 100 MB to 250 MB capacity and work essentially like big floppy disks. They use proprietary format ZIP cartridges. The disks cost about $10 to $15 each.
  • LS-120 (SuperDisk): These hold 120 MB and also double as standard floppy drives. They’re a good choice if your backup needs are very modest and you don’t have a lot of room in your PC case because you can replace your regular floppy with the LS-120 drive. The disks cost about $10.
  • CD-R/CD-RW: A recordable (CD-R) or rewritable (CD-RW) drive can function as a backup device, along with its other uses. Standard blank CD-R media holds 640 MB; high-capacity media holds 700 MB.
  • Jaz: These are like an extra-large version of a ZIP disk and are made by the same manufacturer (Iomega). They hold 1 GB or 2 GB, depending on the model, and the cartridges cost about $90.
  • Castlewood Orb: This is a proprietary format. The disks look like a cross between a ZIP disk and a Jaz disk and hold 2.2 GB. This drive has a high data transfer rate, making it especially good for use as a regular storage drive, as well. Cartridges cost about $40.

Some of you will notice that I didn’t list SyQuest devices. SyQuest used to be a major player in high-capacity removable disk drives, also, but the company filed for bankruptcy in 1998.

Whichever backup disk medium you choose, make sure that it either comes with its own backup software or that it has been specifically tested to work with the backup program you prefer. Not all backup programs work with all device types. If you’re in the market for good backup software, try Veritas Software. It produces several backup programs, including Simple Backup (for the casual user) and Backup-Exec (for the professional).

If you have a CD-R/CD-RW drive, you can use imaging software to create a complete image of your hard-disk content on CD using a program such as Norton Ghost. Drive imaging is most handy for preserving a pristine copy of your system immediately after installing the basic operating system and a few key applications. However, because a CD-R is limited to 700 MB at the most, you can’t store the entire contents of an average system on a single disc. And since imaging, by definition, backs up the entire disk, it is not a very flexible backup method.

Hard-disk mirroring
If you know that you will never be able to stick to any backup regimen, no matter how simple, but you nevertheless have irreplaceable data to safeguard, consider using disk mirroring.

You can buy another hard disk of the same capacity as your original and set up disk mirroring, either through Windows 2000 or through a third-party program. Every write to the disk is mirrored on the backup disk, so if your original disk goes bad, a perfect copy exists on the mirrored volume. The main advantage here is that there is no backup program to run. The main disadvantage is that there is a performance hit in disk writes. If performance turns out to be a problem, you might consider a RAID-5 array of hard disks instead, which can provide redundancy without decreasing disk performance.

Hard disks start at around $100 for a 10-GB model (if you can still find one). The tricky part about this is that for mirroring to work, you must find a disk of almost the same capacity as your original, and if your system is more than a few years old, it might be hard to find a new hard disk that’s small enough.

Conclusion
With all the new types of high-capacity media available, it should be easy to find a low-cost method for backing up your system that won’t be difficult to manage.
For more information on backups, read these TechProGuild features:Please feel free to post your comments to this article recommending a particular brand or model of backup device.The authors and editors have taken care in preparation of the content contained herein but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

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