Choosing Backup Hardware and Media

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Any device that can store data can be used to back it up, but that is like saying that anything with wheels can take you on a cross-country trip. Trying to fit a gigabyte worth of data on a big stack of 1.4MB floppy disks is an exercise in frustration, and using a $5,000 automated tape device to save a single copy of an email is a waste of resources.

Many people use what hardware they already have for their backup operations. Many consumer-grade workstations have a floppy drive and possibly a CD-RW drive, but they typically do not have the abundant free disk space necessary for performing and storing multiple full backups.

In this section, you learn about some of the most common backup hardware available and how to evaluate its appropriateness for your backup needs. With large storage devices becoming increasingly affordable (160GB IDE drives can be had for around $100) and prices falling on DVD recorders, decisions about backup hardware for the small business and home users has become more interesting.

Removable Storage Media

At one time, every computer came with a floppy drive, but those drives are becoming less common and are no longer being provided as standard equipment with many new computers. Some sysadmins remove them because they can be used as a means of penetrating system security. (Remember that physical access to a machine means that it is insecure; a floppy drive provides a way to bypass the system administrator to load and run malicious programs.) Many modern laptops do not provide floppy drives except as an option.

Floppy drives are cheap and disposable solutions for making simple, quick backups of a few files by the user, but the media are easily damaged, lost, and accidentally overwritten.

They also unexpectedly fail at times. Floppies now represent the low-rent district for data storage.

Zip Drives

You can use removable or portable drives as part of your backup strategy. Of all the removable hard drive manufacturers, Iomega seems to have acquired some staying power with its Zip (100, 250, and 750MB) drive. Although these drives have good support in Fedora Core Linux, in the past they have been plagued with mechanical problems that have rendered data irretrievable. Their reliability has improved, but shy away from any older drives. These drives have been ubiquitous and are common in the publishing industry. They are now less frequently encountered and are being supplanted by CD writers.

USB and Solid-State Drives

USB hard drives and solid-state "pen" drives are the new kids on the block with prices dropping over the last year or two; a 64MB "pen" drive costs slightly less than $30 and capacities up to 1GB are available for around $90. USB drives have a large capacity for their size. If your machine supports them (or if you have purchased a card reader), you can also use Compact Flash devices, which come in sizes up to 8GB in the Flash memory versions and 4GB for Hitachi Microdrives. Both USB hard drives and solid-state drives are highly portable. Support for these drives under Fedora Core Linux is very good, accommodating these drives by emulating them as SCSI drives the system usually sees them as /dev/scd1. Watch for improved support and ever falling prices in the future. The newer USB 2.0 hard drives are significantly faster than the older USB 1.0 hard drives. A 100GB USB hard drive will cost about $150. The biggest benefits of USB drives are data transfer speed and portability.

FireWire Drives

FireWire (IEEE-1394) hard drives are similar to USB drives; they just use a different interface to your computer. Many digital cameras and portable MP3 players use FireWire. Kernel support is available if you have this hardware; a 100GB FireWire drive will cost about $180, roughly twice IDE drive prices. Found mostly on the Mac, controller and drive hardware exists for the PC platform as well.

CD-RW and DVD+RW/-RW Drives

Compared to floppy drives and some removable drives, CD-RW drives and their cousins, DVD+RW/-RW drives, can store large amounts of data and are useful for a home or small business. Once very expensive, CD writers and media are at commodity prices today, although automated CD changing machines, necessary for automatically backing up large amounts of data, are still quite costly. A benefit of CD and DVD storage over tape devices is that the archived uncompressed file system can be mounted and its files accessed randomly just like a hard drive (you do this when you create a data CD, refer to Chapter 10, "Multimedia Applications"), making the recovery of individual files easier.

Each CD-RW disk can hold 650MB 700MB of data (the media comes in both capacities at roughly the same cost); larger chunks of data can be split to fit on multiple disks. Some backup programs support this method of storage. Once burned and verified, the shelf life for the media is at least a decade or longer. Prices increase with writing speed, but a serviceable CD-RW drive can be purchased for less than $100.

DVD+RW/-RW is similar to CD-RW, but it is more expensive and can store up to 4.4GB of uncompressed data per disk. These drives are selling for less than $100. Writing to DVD drives requires special software, and, unfortunately, Linux development is somewhat behind the curve for DVD writing. Fedora Core does provide the latest software to write to DVD+RW drives. (DVD-RW support is still experimental.)

Network Storage

For network backup storage, remote arrays of hard drives provide one solution to data storage. With the declining cost of mass storage devices and the increasing need for larger storage space, network storage (NAS, or Network Attached Storage) is available and supported in Linux. These are cabinets full of hard drives and their associated controlling circuitry, as well as special software to manage all of it. These NAS systems are connected to the network and act as a huge (and expensive) mass storage device.

More modest and simple network storage can be done on a remote desktop-style machine that has adequate storage space (up to eight 250GB IDE drives is a lot of storage space, easily accomplished with off-the-shelf parts), but then that machine (and the local system administrator) has to deal with all the problems of backing up, preserving, and restoring its own data, doesn't it? Several hardware vendors offer such products in varying sizes.

Tape Drive Backup

Tape drives have been used in the computer industry from the beginning. Tape drive storage has been so prevalent in the industry that the tar command (the most commonly used command for archiving) is derived from the words Tape ARchive. Modern tape drives use tape cartridges that can hold 70GB of data (or more in compressed format). Capacities and durability of tapes vary from type to type and range from a few gigabytes to hundreds of gigabytes with commensurate increases in cost for the equipment and media. Autoloading tape-drive systems can accommodate archives that exceed the capacity of the file systems.

TIP

Older tape equipment is often available in the used equipment market and might be useful for smaller operations that have outgrown more limited backup device options.


Tape equipment is well supported in Linux and, when properly maintained, is extremely reliable. The tapes themselves are inexpensive, given their storage capacity and the ability to reuse them. Be aware, however, that tapes do deteriorate over time and, being mechanical, tape drives can and will fail.

CAUTION

Neglecting to clean, align, and maintain tape drives puts your data at risk. The tapes themselves are also susceptible to mechanical wear and degradation. Hardware maintenance is part of a good backup policy. Do not ever forget that it is a question of when not if hardware will fail.


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    Red Hat Fedora 4 Unleashed
    Red Hat Fedora 4 Unleashed
    ISBN: 0672327929
    EAN: 2147483647
    Year: 2006
    Pages: 361

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