As I visit both newer and older clients alike, I often
find that backup strategies have fallen into limbo over the years. This is
usually caused by one of the following:
1) The backup tape drive or device that the company was
using has broken down and no one noticed or made a decision to have it repaired
or replaced.
2) The person who looked after the backups left the
company and their replacement was not informed as to how system backups were
performed and validated.
3) Backups and
backup validation seems monotonous and people just consciously or
subconsciously choose not to do them or just forget about them.
Over the years I have seen several companies lose their
complete accounting system when their computer or server crashed and it turned
out that their backups were defective or just not being done with any
regularity.
Similarly, individuals seldom backup personal files and
e-mail on their local computer which can be lost in the case of theft or
hardware failures. Occasionally, a computer will crash and we can still
retrieve files from the hard drive but often these files are gone for good.
With the advent of larger individual hard drives,
portable hard drives and USB Flash drives, which are all fairly inexpensive,
some simple secondary backup strategy can go a long way to make sure you don’t
suffer a major data loss. A high percentage of companies that suffer a complete
data loss fail within a year of the event so I can’t stress the importance of
these procedures enough. Even the loss of a single complex spreadsheet can
result in days of work reconstructing the lost file and the data it contains.
The best form of backup for a File Server is one that
utilizes a series of rotating tapes or other media. A simple rotation would be
to have 5 tapes or disks labelled Monday, Tuesday, Wednesday, Thursday &
Friday. Switching the media each day ensures that you have at least 5 backups
that you can use if you need to.
Since most tape drives typically erase each tape before
backing up, this strategy would not allow you to recover a file deleted several
weeks ago but not missed until today. More complex rotations alternate Week 1,2,3 and Month 1,2,3 etc. backup media alternating these
tapes on Fridays while still using Monday thru Thursday media during the week.
This would typically allow access to files deleted at any time within the last
three months providing an extended period of protection.
ALTERNATIVE BACKUP MEDIA
Interchangeable disk cartridges and rewriteable CD’s and
DVD’s are advantageous in that they can capture files and data without erasing
what was backed up the previous time the media was used. This provides better
protection in simple rotations providing the media has sufficient space to
contain both current and older files.
Occasionally users delete files deliberately and it must
be noted that these files will still remain on the previous backup media unless
the media is deliberately erased before the next backup. This is not usually a
problem unless the files are of a confidential or personal nature.
Interchangeable disk cartridges are probably more
reliable than CD’s or DVD’s but the latter are far less expensive and could
even allow you to keep separate daily backups for an entire year at 25-50 cents
per disk.
As I have noted in previous articles, maintaining at
least two different types of backup media helps make sure that data recovery
will be possible when and if the need arises. This may entail rotating tape or
disk backups combined with a nightly backup to a large user hard drive,
portable hard drive or even a high capacity USB drive. The more physical places
your data resides, the more likely you will be able to easily recover it.
This leads logically into off-site backups. Backups are
of little use if they are destroyed along with your server. Similarly I have
had clients lose both their computers and backup media to theft when both were
left out on the desk next to each other. A fire proof vault may be safe against
theft, but many such safes still get hot enough to melt CD’s and other plastic
media. They are often only fire proof rated for paper and little else.
In most of my server based networks I usually setup user
folders on the file server to store Word and Excel files and such. Then if you
have a good server backup scheme these files will be protected. Many
individuals still store many files on their local hard drives however. If you
use Outlook or Outlook Express for e-mail, your e-mail files are likewise
stored on your local hard drive.
The simplest form of backup in the case of individual
computers is to use a