Playing It Safe

By Team Digit Published Date
01 - Mar - 2005
| Last Updated
01 - Mar - 2005
Playing It Safe
A computer is the single most complicated piece of equipment we use. It has moving parts, magnetic storage, heat dissipation, and has to contend with fallible operating systems and software. Today, critical data stored on a computer connected to the Internet has a lower probability of survival than a kitten crossing a busy highway. All this we are well aware of. We have all been inducted into the religion of backups-either through articles like this one, or due to prior, horrendous data loss encounters. What we don't realise, however, is that every office has different needs. What's good for the goose is not necessarily good for the gander.

Subjective Selections
Every office has its own requirements-you may be spending too little or too much on your data backups. So what are your requirements?

The first step towards identifying a solution is to identify your needs. The first thing you need to do is analyse the amount of critical data that needs to be backed up. Once you have a clearer picture of your data, you can segregate the data into three broad categories.

The first is data that is used on an everyday basis, and needs to be backed up more than a couple of times a day, such as databases. The second is data that might be needed about once a week, and will be modified. The third is data that no one needs more than once a month (or even a year), and might or might not be modified, such as invoice archives for tax purposes.

You have to put your business, and the data it generates and uses, under the microscope and figure out what data fits into which category.
Depending on the volume of data to be backed up in each case, you can come to a solution.

Most businesses already have file servers or network servers that act as a critical data repository. Because of the large amount of reading and writing-and the resulting heat-that servers' disks are subject to, they are prone to failure. What you need to do is get a backup option for these servers. We look at some of the backup technologies available, and what needs they might fulfil.

DAT: Digital Audio Tape; has a maximum capacity of 40 GB and offers data transfer speeds of 19 GB per hour
DLT / SDLT: Digital Linear Tape/Super DLT; has a maximum capacity of 320 GB and offers data transfer speeds of 115 GB per hour
AIT: Advanced Intelligent Tape; has a maximum capacity of 260 GB and offers data transfer speeds of 112 GB per hour
LTO (Ultrium): Linear Tape Open; has a maximum capacity of 400 GB and offers data transfer speeds of 216 GB per hour

NAS (Network Attached Storage)
Basically, a NAS is nothing more than a very simple computer with many hard disks and a simple OS, used mainly to increase the capacity of existing servers, or to supplement the storage capacity for users over a LAN. The hardware and OS are made specifically to enable fast file transfers and handle many simultaneous requests. A NAS device can also be used as a backup device that can be plugged in when backups are needed, and stored away for safety after the backups are done. The beauty of a NAS is that it costs less than a backup server, while still providing all the desired functions.

NAS devices are available from all the top vendors in the country, such as HP and Iomega. A typical NAS generally offers anywhere from 250 GB to 2 TB of storage space. The advantage of a NAS is that it uses drive-based storage, which offers data transfer speeds that are much higher than traditional tape-based storage. Also, NAS devices are very easy to add to an existing LAN, as they are more or less plug-and-play.
Backup Software 
Backup software have just as important a role to play as does the hardware. All the best and fastest hardware in the world will not help much if you choose a software that does its job inadequately. Though companies with really big backup requirements could have existing software customised to their setup, there are a few good software that will do the job straight out of the box.
Most hardware vendors will provide you with their own software when you purchase their hardware, and these are often good enough. You should look for distributed backup software as a total backup software solution for your company. 
Distributed backup software will give you, at the head office, total control over backup policies at your branch offices. This is done via the Internet, and lets the head office engineers dictate a uniform backup policy for all offices. System engineers at branch offices have only the task of managing the servers and media (tape, optical media, external drives, etc.), and other routine local tasks.
Computer Associates (, Veritas (, Legato ( and HP ( welcome.html) are just a few of the biggest names that offer easy-to-set up and robust enterprise-level backup software solutions
Tape Drive Servers
These servers use magnetic tapes to store large volumes of data. They are great for high volumes of data storage, but have slower read and write speeds. Tape media is also a high-risk storage medium, as the media is frail, and needs to be stored carefully.

Systems engineers also need to constantly monitor the media and avoid overuse of a tape, as this could lead to wearing away of the magnetic layer and thus, loss of data. Also, tape drives need to have regular maintenance done, especially the heads that read the tape-these need frequent replacement or cleaning.

The biggest advantage of tape servers has always been cost. For volumes of data backup in terms of terabytes, nothing beats tape on per-GB cost. Also, the portability of tape cartridges means that off-site storage of archived data is easier, faster and cheaper.

Hard Drive Servers
Hard drive servers have fast read and write speeds, and require less maintenance than tape drives. However, the drawback here is cost, lack of portability, and the maximum capacities. Most companies use them as file servers for data that requires constant access, due to the higher speeds they offer. They aren't as cost-effective as tape drives, but are a lot more reliable. As far as portability goes, even with a Hot Swap drive server, the safest place to store the hard disks is probably inside the server cabinet itself!

For a company that needs to have a short turnaround time after a disaster, disk drives are often the only alternative. As businesses turn global, data is required 24/7, and not all companies can afford the time spent on backing up to or recovering from tape servers. For such scenarios, though more expensive, disk servers offer the required data access speed, both while backing up and while recovering lost data.

What Do I Need?
Now comes the hardest part-choosing a solution, or a combination of solutions, for your company. There are three broad categories that any business would fit into, based upon the amount of data that needs to be backed up, and the frequency at which backups are performed. Let's take a look at the three hypothetical companies and their backup solution setups.

Small Business
Company A has two or three network servers, and has less than 80 GB of critical data. Their daily backup is less than 40 GB, and they require archiving of data at least once a month. The company has a per-user backup policy-each user is solely responsible for backing up his or her own data on the servers. The solution they use is an additional network server with dual hard drives running with RAID 1 configuration. Backups are taken at the end of every working day. At the end of the month, data for archiving is manually burnt onto DVD media.

Online Storage 
With broadband penetration in India increasing, online backup solutions are looking more attractive, especially for offices. The advantage of this solution is that your data is accessible from anywhere in the world-only to you. It is also the most convenient in terms of ease of use and infrastructure. All you need to do is run the provided software, select which folders you want backed up, and then back up the data. There is no hassle about maintaining hardware. The drawbacks are that you are dependant solely on your Internet connection, and you might not trust the Internet for critical company data that may contain trade secrets, proposals, etc.
The costs are falling here too, but are still a lot more than using tape or hard drives as backup solutions. If you do opt for this backup technique, make sure to check for hidden costs, data redundancy at the provider's end, encryption and security, and, of course, company reviews and experiences.
Fifty GB of backup space can cost anywhere between Rs 80,000 and
Rs 3,80,000, depending on whether you need a single-user or workgroup backup solution. Some online backup providers are: or

Company A runs personal software on every user's computer to back up data onto their network file servers. Then, software on the backup server copies the data from the network servers-it is scheduled to do so about an hour after the day's work is completed. In the final step, every month, backups are done manually by a systems engineer onto DVD media.

File server, dual RAID 1 120 GB hard drives
One system with DVD writer and DVD media
Personal backup managers
Professional backup application for servers
One systems engineer
Medium-Sized Business
Company B has five network servers and needs to regularly back up between 80 and 250 GB of data. They generate or use over 80 GB of data a day, and need it all backed up and stored safely in case of a crash. This company relies solely on its data to function.

Individual employees use the various network servers to access work data. These SCSI network servers have a capacity of about 120 GB each, and have external hard drives connected to each server, taking hourly backups of each server's data. In addition, there is a NAS for redundancy and failure protection, which takes backups from the network servers at the end of each day. All this data is then backed up or archived on tape drive about once a week. The tapes are stored in a separate location, in order to enhance data security. This entire cycle of weekly full backups requires about five backup system engineers to monitor and maintain systems.

Three file servers with dual RAID 1 SCSI hard drives
Tape drive with tape cassettes
NAS device
Personal backup managers
Professional backup application for the servers
Five systems engineers

Company C is a corporate company with offices widely distributed across the globe. Let's say they have 10 worldwide offices, and all 10 need access to about 80 GB of core company data, apart from the backups of each office. The total amount of data that needs to be backed up here could be in the terabyte range. The company also needs the backups done every hour, and effectively works 24/7 due to the different time zones of its branch offices. The central backup with core company data is located in the head office.

Backup or Archival? 
People often do not understand the difference between backup and archival. Many small offices have a DVD-Writer as a backup solution for working data, and overspend on media. Due to these costs, backups are infrequent and loss of data may mean an unacceptable setback of days. On the other hand, some offices may have a server or external hard disk solution for archival purposes. This results in running out of hard disk space and in deletion of archives.
You need to identify whether your requirements are backup- or archival-based. A simple rule of thumb here is to use the previous self-assessment you did: if your backup requirements are infrequent and less than 5 GB, you are better off using DVD-R or DVD-RW media. 

Here, each individual office will have backup systems akin to medium-sized businesses, with the only difference being that specific data will be uploaded at pre-defined intervals to the head office servers. Each office will also have a NAS device as additional backup security.

If the core data is less than 20 GB, and daily uploads from each branch office are less than 300 MB, the company could opt for online storage or online backup. This would make it easier for the company to manage and share core data securely and easily. It also reduces the required infrastructure and manpower needed to monitor and maintain an online server.

The alternative is to locate the online server at the head office, under 24/7 monitoring by systems engineers. Here, each branch office needs about five engineers, and the head office needs to have systems maintenance engineers, security professionals, Web developers, etc.

Rough Estimates 
Here's what you are looking at in terms of costs, for implementation of the backup solutions mentioned here. 
Product Type Capacity Rupees Brands 
Tape Servers DAT
DLT / Super DLT
40 GB
80 GB
400 GB
Tape Libraries Super DLT, 8 slots
DLT, 100 slots
LTO, 72 slots
2.5 TB
8 TB
28.8 TB
Tape Media DAT (19 GB per hr)
DLT/SDLT (115 GB per hr)
AIT (112 GB per hr)
LTO (216 GB per hr)
40 GB
320 GB
260 GB
400 GB
TDK / Maxell / Fuji
TDK / Maxell / Fuji
TDK / Maxell / Fuji
TDK / Maxell / Fuji
RAID Servers Ultra ATA 1.2 TB 165,300 Iomega, Dell, HP 
NAS SATA-150, Hot Swap 1 TB 282,750 Iomega, Dell, HP 

Multiply the hardware and software requirements below by the number of branch offices you have.

Five file servers
Two Automated Tape drives
A T1 line
Online Storage
Professional Distributed Backup Software
A full-fledged IT department

These three models broadly categorise all medium to large-sized businesses across the globe. Your business may be exactly like one of these, or be somewhere between any two.

If you choose carefully, and wisely, you can use various combinations of the hardware and software mentioned here to find a perfect backup solution for your requirements.

Team DigitTeam Digit

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