Integrated Solutions
by Steve Webb
October 2004
Businesses can bring their backup systems into compliance by using SATA drives and new tape media.
Companies have more incentive than ever to develop redundant storage systems.
Without backup storage capabilities, businesses run the risk of losing critical
data -- and the threats to this essential data keep on growing. In addition to
the danger posed by a fire or a natural disaster, there is the possibility of
losing mission-critical data to terrorism or computer viruses. If those threats
don't provide businesses with enough motivation to implement redundant storage
systems, recent regulations no doubt do. Sarbanes-Oxley, an act that establishes
best business practices, and Securities and Exchange Commission (SEC)
regulations require banks, government agencies, hospitals, and other
organizations to provide redundant access to data or face heavy fines.
"These new regulations are basically forcing affected organizations to back up
and retain data for longer periods of time," says Morgan Edwards, president and
CEO of UltraBac Software (Bellevue, WA), a developer of backup and disaster
recovery software. End users have a number of new technology options to bring
their storage systems into compliance, including SATA (serial advanced
technology attachment) drives and a new line of LTO (linear tape open) media. In
addition to the new hardware, image-based software is available to reboot
computers to their previous backup state in the event of a disaster.
Serial ATA: High Capacity Storage
SATA, a standard for connecting hard drives that uses serial signaling
technology, has emerged as a disaster recovery option in the past two years.
SATA drives contain thinner, more flexible cables than those used in
conventional hard drives. Edwards says SATA drives are best used for RAID
(redundant array of independent disks) storage, a system that enables companies
to back up data on multiple disks. "SATA is being used effectively in external
RAID arrays that offer large amounts of redundant storage very inexpensively,"
says Edwards. SATA drives are roughly 80% cheaper than Fibre Channel drives, one
of the other RAID technology options.
"SATA has reduced the cost of RAID storage, with performance characteristics
that are an ideal match to most disaster recovery requirements," adds Bob
Farkaly, director of worldwide disk product sales for Overland Storage, Inc.
(San Diego), a manufacturer of automated tape libraries and disk-based recovery
systems. Farkaly says SATA drives are a good match for disaster recovery systems
because they provide a connection via iSCSI (Internet small computer system
interface), a protocol that enables block storage applications to interface over
TCP/IP (an open computer communications language). "iSCSI is the perfect
transport mechanism for moving data to a disaster recovery site because it
combines high performance with the distance-spanning capabilities of IP
networking," says Farkaly.
In addition, a SATA drive has a capacity of 400 GB, says Farkaly, which is more
than double the capacity of a Fibre Channel drive. "You get better storage
densities with SATA drives. SATA-based RAID arrays are great for bulk storage,"
he says. "The thing I particularly like about SATA is that it uses switched
network connectivity. Instead of having a host bus adapter [HBA], you have
individual data paths to each drive, and that's important when you have a
storage area network with requests coming in from several different servers and
locations."
Hybrid Storage Media Meet Redundancy Requirements
The comparatively low cost of SATA drives is likely to encourage more companies
to store data on disk media. One of the main advantages of disk is that it
provides high-speed access to stored data. Still, companies will continue to use
tape technology for long-term storage because it is even less expensive than
SATA disk technology. Hybrid disk-tape systems for long-term storage can allow
companies to capitalize on the strengths of both types of media. "The two
technologies are very complementary," says Farkaly. "Tape is the cheapest way to
store data. One drawback to tape, though, is that it doesn't provide immediate
access to data -- you always have this sequential paradigm that you have to go
through." Disks allow users random access to data, instead of the sequential
system used by tapes. Copying data to tape takes far longer than backing up to
disk. For that reason, disk staging can be an effective hybrid solution. In that
system, data is first transferred to disk media to take advantage of the faster
backup times for that media, and later transferred from disk to tape. The tapes
can then be stored off-site to meet requirements for redundant storage.
Advancements in tape technology will continue to make tape an attractive
long-term storage option for companies. "Tape technology has not only managed to
keep pace, but has even exceeded end user requirements for backup storage
space," Edwards says. "New, large libraries based on emerging tape technologies
will be able to offer many terabytes of storage at a fraction of the cost of
disk-based technologies." LTO-2 (linear tape open) media provides 200 GB of
capacity, compared with 100 GB for LTO media. And the next generation, LTO-3,
will provide 400 GB of capacity when it enters the market in 2005.
Edwards says manufacturers have developed WORM (write once, read many) tape
drives that enable tape media to be used in disaster recovery applications that
require data to be stored on unalterable media. "So, now you're talking about
being able to back up massive amounts of data to WORM technology," says Edwards.
"Users now have the choice to use high-capacity, low-cost WORM media that is
capable of meeting the requirements of these new laws."
Reboot Computers With Image-Based Technology
Storing data redundantly reduces the risk of losing crucial data, but companies
also need software to reboot computers in case of disaster. Companies typically
use file-by-file backup software to reboot computers, but image-based BMR (bare
metal recovery) is a faster system for restoring computers. File-by-file backups
require the operating system to be reinstalled. In the BMR option, an automated
scheduler takes snapshots, or exact images, of operating system partitions and
transfers them to tape or disk. These snapshots can be scheduled once a day, or
however often a user wants to save data. By using these snapshots, BMR can
restore an operating system partition in 15 minutes, compared with about 2 hours
for file-by-file backups. "This technology allows you to quickly restore the
operating system partition back to a previous state," says Edwards. "Every
organization is using standard file-by-file backups today. Ideally, every
organization should have both a file-by-file and image-based backup solution to
better insulate their organization from data loss and downtime."
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