The boom in the IT sector has led to a rising demand for data
storage and data backup services. However, choosing the most
appropriate services for your company requires a strategy of its
own
The tremendous growth of the IT industry has created an
increasing demand for data storage capacity and consequently,
better data backup services. Developing a successful backup
strategy begins with a carefully planned backup needs analysis. The
administrator first identifies the company's total backup needs and
then matches those needs to the appropriate backup hardware and
software.
There are various hardware technologies available for data backup.
The most common and inexpensive one is the QIC or Quarter Inch
Cartridge. Although rather slow, it is ideal for small businesses.
Medium-level enterprises might want to consider DAT or Digital
Audio Tape. Much faster than QIC, DAT tapes can also store more
data. Businesses with multiple offices and larger server capacities
should adopt technologies like DLT or Digital Linear Tape. DLT
tapes have capacities up to 30Gb and are much more reliable. There
are also high capacity proprietary solutions available from
companies like OnStream.While choosing data backup software, it is
important to assess the quality of technical support available and
the reliability of the backup device.Although not quite as visible
as many other operations, data backup is just as important to the
success and well being of the organisation.BODY TEXT:The tremendous
growth of the IT industry has created an increasing demand for data
storage capacity and consequently, better data backup services.
Fuelled by the ever-expanding growth of Internet-related
technologies, electronic messaging, multimedia, Online Transaction
Processing (OLTP) and other data-intensive applications, the
enterprise backup and storage market is expected to expand rapidly
during the next two years.
Why are backups essential?The
backup process copies important information (in many companies,
this is vitally important information) onto magnetic tape or other
disks. This enables the restoration of anything, from one file to
the entire system, should the need arise. Backups have helped
companies recover from data losses caused by power surges and
outages, static electricity, lightning strikes, terrorist bombings,
user errors, viruses and even spilled coffee.Data recovery tools
and services do exist. But they are limited and can be expensive.
Using these services, users might be able to retrieve some of the
lost data. But it is unlikely you will ever retrieve all of the
lost data. Complex applications, network configurations, customised
set-ups and passwords may be impossible to retrieve. The sudden
loss of a mission critical server that stores and maintains
corporate records and data (one of a company's most valuable
assets) can be financially disastrous. In most companies just the
downtime before recovery could prove too costly. A well-designed
backup system safeguards crucial information, providing the most
efficient insurance against disaster.Developing a successful backup
strategy begins with a carefully planned backup needs analysis. The
administrator first identifies the company's total backup needs and
then matches those needs to the appropriate backup hardware and
software. In many companies as much as 40% of the data changes
every month. Ultimately, all company data and programs should be
backed-up so that the entire system can be restored in the event of
a catastrophic disaster. The total amount of data to be backed-up
indicates the capacity required of the drive and the media. If
planned backups will be unattended, then the selected backup device
must have enough capacity to hold the full amount of information to
be backed-up. Another crucial factor to consider is the performance
of the backup kit, both hardware and software. System
administrators typically perform backups when user demands on the
server are at their lowest. Ideally, this time period, often called
the backup window, is when user access can be restricted or the
server shut down. For many companies with worldwide operations
accessing their servers, no clear backup window exists. In such an
instance, the administrator will have to perform the backup while
the system is still in use. This often leads to some degradation in
overall performance. Where a backup window does exist, the selected
device's backup rate, together with the appropriate backup
software, must be able to accomplish the task within the time
available. The amount of data that needs to be backed up, along
with the time available for doing it, often determines the type of
media and software that can be used.Performance is determined by
dividing the amount of information (in gigabytes) that must be
backed up by the size of the backup window (in hours). This simple
calculation yields the required performance as an overall transfer
rate expressed in gigabytes per hour.
Technologies for data
backup?Currently, there are three types of backup technologies
that are frequently used. The oldest and most common among these is
Quarter Inch Cartridge (QIC). These drives have the lowest
capacities and slowest transfer speeds. QIC drives meet the
half-height form factor of desktop computers. QIC tapes are
virtually industry-standard for standalone machines. However, with
capacities limited to 1.2Gb, they are not generally suitable for
backing up servers with 2Gb or more storage capacity - a capacity
exceeded by ordinary desktop PCs nowadays.Low capacities and slow
speeds are not the only disadvantages of QIC drives. They also
require regular maintenance. Like normal audio tape heads in
consumer tape recorders, QIC drive heads must be cleaned regularly.
This is particularly important if the tapes themselves are being
reused often. QIC drives are slow, not just because of their
overall data transfer rate. Most of them only allow sequential
access to data. Therefore, it is not possible to selectively
replace backed-up data. Despite these disadvantages, QIC drives are
still very popular because they offer excellent value for money.
For many small businesses for whom cost is a big concern, QIC
drives offer the best solution. Even for larger enterprises, QIC
can be useful for short-term archiving.The second most popular
backup hardware format is DAT (Digital Audio Tape). DAT drives are
usually the appropriate choice for servers with 2Gb to 8Gb
capacity. A high density DAT tape can store up to 16Gb of data with
efficient compression. Like QIC drives, DAT drives also offer good
value for money. In addition to bigger capacities, they offer
better reliability and, more importantly, random access to stored
data. So, who should consider using DAT for backups? Medium-level
enterprises who have modest backup windows and budgets are ideally
suited for DAT backups. Even fast growing small businesses with
increasing backup requirements might want to consider migrating to
DAT at some stage from QIC or other less capable solutions.One of
the Goliaths among backup technologies is Digital Linear Tape
(DLT). These drives can store up to 30Gb of data. The basic DLT
technology has been around for a decade. It was first introduced by
Digital Equipment Corporation (DEC). When coupled with RAID
technology, arrays of identical DLT drives offer a high degree of
fault tolerance and data accuracy. In addition to much higher data
backup capabilities, the basic DLT design is inherently more
reliable than those of DLT's counterparts from the older
technologies. In DAT and other helical scan drives, the tape is
wound tightly around a drum and moves through a complex tape path,
resulting in stress and abrasion to the tape and the heads. DLT
tape operates at a lower constant tension. Therefore its life span
is much higher.The technologies mentioned above are not the only
ones available for backup purposes. Many companies offer
proprietary backup solutions. For instance, OnStream's tape backup
kit now offers capacities up to 70Gb with compression - a real
competitor to the older and more expensive DLT technology. However,
those who intend to adopt such apparently cheaper proprietary
technologies must also enquire about hidden costs and the level of
technical support available in each region.Deciding the type of
backup device is only one step towards solving the problem. After
this, the system administrator has to adopt a schedule and
methodology for creating the backups. For instance, if the backup
windows are really small or non existent, the system administrator
may opt for a dedicated network just for backup purposes. This
dedicated network, which is completely independent of the normal
LAN, has two major advantages. Firstly, it almost completely
eliminates the need for a backup window as the backup process can
be completed while users are still logged on to the network.
Secondly, because there is a dedicated channel for transferring
backup files, the bandwidth on the main LAN remains untouched and
performance is not affected. This dedicated network can be
constructed using regular networking cables or fibre channel
cables. Of course, high bandwidth technologies, like fibre
channels, tend to be much more expensive.Choosing the right
hardware is only one half of the backup solution. If you do not
have fully tested software to run on the appropriate platforms,
even the most robust hardware set-up may not be able to prevent
loss of data. Like hardware, backup software is available from a
number of different vendors to suit all needs and budgets. Quite a
few of the advanced backup software packages are offered by the
major hardware vendors themselves. And they are available for most
popular server operating systems like Windows NT and UNIX.
Backup
SoftwareIn most companies, the backup process is done remotely
without human intervention. Therefore, more than anything else, a
backup software package must be able to schedule all the tasks
involved. At times specified by the system administrator, the
software must initiate the backup process. The software must be
capable of continuously monitoring the entire process and reporting
any problems it encounters. If the problem is a software one (such
as conflict with another application), the package must be
intelligent enough to recognise it as such and take the appropriate
measures to correct it. Even some hardware problems can be fixed by
good quality backup software.Most backup software vendors offer
regular updates for their products. However, not all the updates
may be appropriate for every organisation. Therefore, it is
absolutely essential to check the quality of technical support
available before purchasing the product. Most of the major vendors
of backup software support the popular UNIX platforms, NT, and
NetWare. If you are backing up data resources on other platforms
you may find your choice is restricted.Data backup is an integral
part of any organisation's IT infrastructure. Although not quite as
visible as many other operations, data backup is just as important
to the success and well being of any organisation. As the amount of
data in an organisation increases, the scale of the backup solution
must keep pace. As the world moves to a 24 x7 web-enabled
e-commerce model, downtime for backup and restore must be kept as
close to zero as practicable. Backup speed can become a critical
issue for business competitiveness.
Ajith Ram