Tape it up

RAID is getting all the press these days. As a data protection technology, a RAID array is an excellent solution. It consists of a number of hard drives that essentially contain the same data, so if one drive fails, the others take its place and data is not lost. However, RAID arrays are faithfully redundant, so if a software glitch of some sort corrupts or destroys data, the data loss will span the entire RAID array. Also, if there’s a catastrophic event such as a fire that destroys the RAID equipped server, all the data will be lost. What can companies do to prevent such data loss? The answer lies in a less glamorous, age-old technology: tape backups.

By copying mission critical data to linear media, IT administrators create snapshots of the company’s computer situation at a given time. If data is lost from a server, it can be restored by pulling it from the most recent tape backup. Tapes are small and highly portable, so copies of company data can be stored offsite, protecting them from catastrophic damage to the company’s offices.
A typical tape backup system consists of a SCSI, ATAPI or fibre channel tape backup device connected to a server, or a dedicated tape server system. A backup software suite such as the popular Veritas Backup Exec automatically streams data, which are selected by the IT administrator, from the network onto the media in the tape backup drive. Backups are usually scheduled to take place at night when the network isn’t in use. In most cases, backups are streamed to a different tape each night for the sake of redundancy; if, for some reason, Tuesday’s tape doesn’t have the necessary data, the IT department can check Monday’s tape.
There are three major types of tape backup devices: drives, autoloaders, and libraries.

Drives.
Tape drives can be internal or
external, fitting in 3.5” or 5 1/4” drive
bays. Internal models can interface
through SCSI or even ATAPI,
although for the sake of speed
and convenience, SCSI is usually
preferred. Internal ATAPI systems
are generally limited to four devices,
two devices on each of two
channels.
External drives generally connect to
a PC via a SCSI channel, although
USB and FireWire drives are
available. Single-drive NAS devices
are available that communicate via
SCSI or fibre channel.

SONY SDZ-S100

Autoloaders.
Similar in essence to multi-disc CD changers, these megadrives contain several tapes and use a robotic mechanism to swap them into and out of the read/write position. The advantage is that IT professionals don’t have to remember to change out a tape each night. Autoloaders are especially handy for large enterprises that contain several tape backup systems. Autoloaders are external devices connected to PCs via SCSI or other buses, or standalone NAS devices.

Libraries.
Essentially a shelf unit, a tape library
can contain a massive autoloader,
multiple drives, and terabytes of
space. Libraries can be NAS devices
or connect directly to a PC via a
high-speed (often ultrawide) SCSI
or fibre channel. Now we’ll take a
look at solutions provided by two
leaders in tape backup technology,
Sony and Quantum.

Sony
Sony tape devices rely heavily on a
technology called AIT, or Advanced
Intelligent Tape. After announcing
the platform in 1996, Sony has been

SONY E130

enhancing and refining it for nearly a decade. The latest revision, which isn’t shipping yet, is AIT 4. AIT drives are compact, with a 3.5” footprint--the same width as a floppy drive. AIT media has an 8mm form factor and is comprised of AME (Advanced Metal Evaporated).
According to the AIT Forum web site (www.aittape.com), AME tapes “include 100% pure cobalt magnetic layer design, the absence of binder material to prevent tape head contamination, and a ‘Diamond-Like Carbon’ (DLC) protective coating for extreme durability. AME also permits very high density magnetic recording, thereby allowing the AIT family roadmap to scale to very large capacity points in the future.”
AIT also calls for MIC (Memory In Cassette) technology, which is a semiconductor chip in the tape that provides fast drive access and information retrieval. The chip also can enable value added backup services such as WORM (write-once-read-only) backup on tape, which prevents accidental file erasures or file alterations. This would be ideal for special data or archive retention requirements that may driven by various regulations.
AIT drives are low-maintenance. They rarely need cleaning, and when they do they employ a built-in active head cleaner. Only rarely and after heavy use do they need to run a cleaning cycle with a special cartridge.

Sony offers a number of AIT and
SAIT tape devices, including:
New SAIT drives, which can
potentially back up entire midrange
servers. Aimed at enterprise
customers, SAIT drives can store up
to 1.3 terabytes (TB) compressed, or
500 GB native. With their massive
capacity, SAIT drives actually lower
the total cost of ownership (TOC), by
requiring fewer devices and media.
SDX-D700C/BM AIT 3 External Tape
Drive. With a 260 GB capacity
compressed or 100 GB native, the
ultra 160 wide SCSI device delivers
high-capacity storage and speedy
transfer rates, bursting at 160
MB/second with a sustained rate of
24 MB/second with 2:1 compression.
AIT is a backward compatible
technology, so this AIT 3 drive can
read and write to media for AIT 1
and 2.

QUANTUM DX100

Quantum
Asked what makes Quantum stand out amongst tape-backup manufacturers, a Quantum representative had this to say: We are in the business of data protection - we know what it takes to meet customer’s demands. Since 1980, Quantum has been a leader in the design, manufacture and service of automated tape drives and tape libraries used to manage, store and transfer critical data. Most recently, quantum has been one of the pioneers in the emerging market of disk-based backup, offering one of the first solutions that emulates a tape library and is optimized for data protection. Today’s networked businesses demand the highest levels of performance, scalability, and reliability to maximize performance and optimize your technology investments. Our extensive product line of autoloaders, tape libraries and disk-based solutions provide simple and scalable data protection for every environment, whether you are seeking to protect gigabytes, terabytes or petabytes. By leveraging new storage architectures and operating systems, Quantum helps customers efficiently and cost effectively manage, store, and protect their valuable data with products that offer:
– Compatibility with all major hardware platforms
– Support for over 40 popular data management software applications
– Capacities ranging from 250GB to 479TB
– Disk-based solutions that boost backup confidence beyond 99%

Quantum not only provides tape
backup systems, but also a unique
tape-emulating disk-based system
called the DX100. The DX100 is
actually a second generation
product designed for flexibility and
performance: it’s super-fast,
crunching backup data at 2 TB/hour.
Equipped with RAID 5 capability,
the DX100 can store up to 64 TB of
data, and it functions with the
hands-off automation of a tape
drive; it’s even compatible with tape
backup software such as Veritas
Backup Exec. Quantum’s wares
aren’t limited to fancy disk-based
systems. They also include
traditional tape backup systems
such as:

QUANTUM SDTL 600

PX720 Tape Library. A fifth-generation product, the PX720 tape library is a solid, automated system with plenty of management and redundancy features. The massive system holds up to twenty drives. Loaded with Quantum SDLT drives, DLTSage is included: DLTSage increases manageability of tape backup systems throughout the network allowing IT professionals to monitor tape drive usage, watch error rates, monitor cooling systems, and so on.

SDLT600. This high-capacity, speedy tape backup system holds up to 600 GB of compressed data. Managed with DLTSage, it connects to the enterprise network via ultra-160 SCSI or fibre channel, with burst rate data transfer rates of 160 MB/second or 200 MB/second respectively.