Every data centre manager, be it at a Fortune 500 or a small startup, must face five core issues during his or her database management. Two fundamental keys of databases themselves are exacerbated by three other forces that require attention in order to have a robust, functional, and powerful database system.

The nature of DBA is simple: ‘If you’re doing your job well, nobody will notice. If you screw it up, everyone will notice.’

=== DB Fundamental: Accessibility

To be useful, a database must be accessible. Otherwise it is just a store of information that no one can retrieve. In database management terms, the value of data is measured by how much it costs (in dollars and/or machine function/processor time) to store and retrieve it. The less it requires to get to the data, the cheaper the data is by these metrics.

This means that the easier it is to find data, the cheaper that data is to the overall scheme. For example, in 2005, Cisco estimates that it spent $25.2 million on data retrieval just for regulatory compliance purposes. After upgrading and improving their processes, they cut that cost by 97% to $1.8 million the next year. Not insignificant.

So accessibility is perhaps the top priority for nearly every DBA and her team.

=== DB Fundamental: Change Management

Two types of change management occur in a database. The first is management of the data’s changes themselves – how they are accessed, changed by users, and stored. The second is how the business around the database changes, affecting the database itself.

The first DBA concern is user management and this ties in closely with security (below). Most DBAs realize the importance of keeping date-stamped backups of original data so that if something is changed and the changes must be reversed, they can be. That’s the basics of change management in data.

In business, changes are constant and for the DBA, this means new hardware, changes in software, upgrades to client machines, and more. All of these can affect the DB, so the administrator must keep a fluid system capable of growth or alteration. Managing the lifecycle of your hardware, for instance, can mean 30% in savings over a year thanks to lowered replacement and disposal costs.

=== DB Forces: Compliance

Likely the most important (and hated) aspect of database management is compliance. There are whole volumes of legal books dedicated to document and data storage requirements as well as retrieval needs for those legal documents the company stores. Literally every department of a business will have compliance requirements for the DB. Often these must be preserved for long periods of time as well.

Balancing the data storage needs of the company with its retrieval requirements is often the most demanding thing a DBA does.

=== DB Forces: Security

If the news is any measure, data theft and losses are on the rise. While this has been a core issue for DBAs since the days of DBA 101 classes in school, it’s becoming a forefront subject as well as the impetus for many changes happening in the business today.

=== DB Forces: Disaster Recovery

‘Backup once, then backup regularly’ is the mantra of all IT workers. In DBA it’s said twice. Nothing is more disastrous for a company than having its database lost and irrecoverable. The ability to quickly restore lost data, change access accounts and passwords, etc. are paramount to both security and asset safety.

These five issues can be considered the core of what all DBAs face and should be what they focus on the most.

In the thirty years since IBM launched their personal computer, data and data storage devices have become such an integral part of people’s lives that it seems almost unbelievable that in the 1980s very few people had their own computer at home. In 2009, the Office for National Statistics reported home computer ownership in the UK to be 75%, rising to 98% in the highest income group. Data and its safe storage has therefore become an increasingly high priority in people’s lives, and the technology industry has responded to this need by creating ever higher storage capacities both in personal computers and external hard drives (EHDs).

EHDs offer many advantages to the user; they can protect a user’s data by providing a back up capability for the main computer, they are useful for storing and archiving large multimedia files and the increasingly popular compact portable versions are particularly useful for data transportation. However, despite all their advantages, we need to be careful with these disks. EHDs are among the most common of all devices sent to data recovery companies. There are two main reasons for this:

1. EHDs are vulnerable to human clumsiness. Desktop EHDs may have liquids spilt on them or they may accidentally be pulled over or dragged onto the floor by trailing data or power cables. Portable EHDs are often placed into trouser pockets or bags which may be sat on or otherwise damaged during transit.

2. In their attempts to keep EHDs as compact as possible, manufacturers often omit the cooling fan which would always be found in a PC or laptop hard drive. EHDs are therefore at risk of overheating which can have repercussions for the stability of the data stored on the disk.

So, how do we know when and why our EHD has failed? And more importantly, what can we do about it? Well, in addition to the drive spinning then dying or not being recognised in the BIOS, there are a variety of noises that damaged EHDs can make, including screeches, beeps, bleeps, ticks, knocks and buzzes. We will take a look at some of these symptoms in more detail and describe the underlying causes:

* Beeps, bleeps and screeches: Many manufacturers use Fluid Dynamic Bearing (FDB) technology in preference to ball bearings as the disks run more quietly and have better shock resistance. However, our research has shown that when the disk is powered on from cold the fluid takes time to reach its optimum viscosity, and during this time is vulnerable to vertical vibration. This can lead to read/write errors and a resultant beep or bleep noise.

* Buzzing: EHDs contain a spindle which is responsible for rotating the platters. Only a small part of the spindle comes into contact with a comparatively heavy part of the drive, and a sudden knock or jolt to an EHD can cause the spindle to seize, and the drive will not be recognised by the computer.

* Ticking or Knocking: Inside EHDs there is an arm with read/write heads which, as their name suggests, read or write data to and from the platters. If there is damage to the heads or the motor, the arm can knock against other components in the disk as it continually tries to read the data, which creates a regular ticking sound. In our experience this is usually caused by the EHD being dropped or knocked over.

* Running slowly and suddenly dying: This may have accompanying noises (such as a repetitive scratching sound) and is caused by overheating due to lack of ventilation around the disk.

There are therefore many problems that can befall EHDs and preventing these by taking care of the disks is important; however should disaster strike the crucial piece of advice from the data recovery industry is to immediately power off the disk, and not to risk running a repair utility which may further damage access to the stored data. Reputable data recovery companies use specialised equipment and clean room laboratory conditions to retrieve valuable data. Their expertise and experience is reflected in the prices they charge; unfortunately there are many companies, typically those at the low end of the market, who greatly exaggerate their abilities. Potential customers would be well-advised to carefully research the reputation and skill-sets of data recovery companies before entrusting them with their crucial files.