Data
Recovery
Data recovery is the act of salvaging data stored on
damaged media, such as magnetic disks and tapes. There are
a number of companies and software products that can help
recover data damaged by a disk crash or virus. Of course,
not all data is recoverable, but data recovery specialists
can often restore a surprisingly high percentage of the
data on damaged media.
Data recovery cases can be divided up into two main
categories:
- Common Recoveries –
Involves floppies and hard drives that are usually from
single-user personal computers.
- Complex Recoveries –
Involves hard drives, RAID arrays, tape and optical
media or corrupted databases and file systems usually
from multi-user, business systems. Data storage at the
high end has become a very complex field. In the case of
these complex systems data recovery can be seen as
"troubleshooting data storage."
Whether common or complex,
each data recovery case is unique and the process can be
very resource extensive and exceedingly technical.
What is Data Loss?
Typical Characteristics of
a Common Data Loss Situation:
- Accidental deletion of
data
- The sudden inability to
access data from a previously functioning computer
system or backup
- Accidental re-forming of
partitions
- Hard disk crash or hard
disk component failure
- Ticking or grinding
noises coming from the system unit where the hard drive
is located while powering up or trying to access files.
This symptom almost always indicates a failing hard
drive and is often accompanied by some of the other
symptoms.
Note – Most drives will
emit a light mechanical hum that a user may notice under
normal operation. An indication of impending failure is
when the “normal sound” changes to louder ticking or
grinding noises. This symptom may precede actual data
access problems as the drive utilizes spare detectors
- Computer won’t boot.
Blue or black screen after power up. The system will not
load Windows or other operating system
- Applications that are
unable to run or load data
- Trying and failing to
start an application such as Microsoft Excel or
Microsoft Word
- Opening folders that
should be full of files but appear to be empty
- Inaccessible drives and
partitions
- Corrupted data
- Visible fire or water
damage
- Media surface
contamination and damage
Increased Incidents of
Data Loss
Despite technological
advances in the reliability of magnetic storage, the
incidence of data loss continues to rise. Data storage
devices are susceptible to damage from natural and human
sources.
Consider these facts:
- More data is being
stored in smaller spaces – Today’s hard drives store 500
times the data stored on the drives of a decade ago.
Increasing storage capacities amplify the impact of data
loss, making mechanical precision more critical. A
slight nudge, a power surge, or a contaminant introduced
into the drive may cause the head to touch the platter
resulting in a head crash.
- Data has become more
mission-critical – Users today store more data on their
desktops and networks that is mission-critical to their
organizations and to their personal lives. Loss of
mission-critical data, by definition, causes major
business processes to stop.
- Backup technology and
practices have failed to adequately protect data – Many
users back up their data only to find their backups
useless at that crucial moment when they need to restore
from them.
They fail because the systems are designed with a set of
requirements that rely on a combination of technology
and human intervention for success. Taped, tape drives
and cartridges do not always work properly, due to their
dependence on mechanical perfection.
Backup software can become corrupted. Users accidentally
back up corrupted or incorrect information
Causes of Data Loss
Data loss happens for a
number of reasons. It has become a major problem over the
last few years as more and more digital information is
being stored on media that fails. It’s estimated that only
3% of the worlds information is backed up. More often than
not, backups are not done correctly – consequently leaving
you with no, or the wrong data.
Causes of Loss in
Databases:
- Backup files not
recognizable by the database engine
- Database locked as
‘suspect’ preventing access
- Deleted or dropped
tables
- Accidentally deleted
records
- Corrupted database files
- Damaged individual data
pages
- Accidentally overwritten
database files and devices
- Flood, Fire or
Earthquake (natural disasters)
Remember that at some point
everyone who works on a computer will experience data
loss. It’s not a question of if data will be lost
but when data will be lost.
A data loss situation is
usually characterized by the sudden inability to access
data involving a previously functioning computer system or
backup or the accidental erasure of data or overwriting of
data structures.
|
