Types
of Data Backup
After
you have determined what
to back up and what
backup storage media fits the best,
you need to decide how the files will be processed. The main things
to think about here are the method of backup and compression options.
Normally, file
backup software
doesn’t back up your PC as a whole, but allows forming tasks
involving variable sets of folders and files. For each backup task,
for convenience in operation, the program creates a so-called index
file which contains information about all data used in it. This file
is then used for comparing current and old data when
doing differential or incremental
backups.
Let's take a look at examples of different methods.
Full
Data Backup
Full
backup assumes
that each time you execute the task, the entire set of data is copied
to the chosen place. This type of backup takes the most disk space,
time and PC resources, and often does a lot of senseless work
(because unchanged, already backed up data becomes multiplied several
times). On the other hand, for some types of data, e.g. when you
create a complete disk
image backup,
full backup is the only effective option.
Incremental
Data Backup
Incremental
backup processes only files that appeared or changed since the
previous backup. Say, you created a task for backing
up My Documents folder.
If you do an incremental backup immediately after a full backup, no
files will be copied. But as soon as some files get modified, or new
files are created, an incremental backup will process all
modifications (which are calculated through comparing data in the
index file with the current situation on the drive).
Incremental
backups may be of two types: when files are rewritten in the same
folder where the full backup is and when files are put into separate
folders (which leads to creation of multiple instances of the same
files). In Handy Backup, the latter option is called backup
with timestamps.
Differential
Data Backup
Differential
backup is very much like incremental backup, with the only difference
that it doesn’t update the index file with each task execution, and
therefore each task execution processes all modifications since the
last full backup. This approach requires more disk space, as each
differential backup is of the same size or larger than the previous
one, but enables faster restoration of data, as compared to
incremental backup.
Data
Compression Options
Since data
backups are
not meant to be used as separate documents, it's wise to enable
automatic compression, in order to save storage space and
transferring time (may be important if you back
up online,
or back
up to FTP locations).
Here you need to decide, if you want to compress the backup set as a
whole, or compress each individual file. The first variant gives the
best results in terms of saving space, while the second one requires
less PC resources and allows you to perform backups and restoration
faster.
After
choosing a backup type, it is important to choose how often the task
will be performed, and specify
a backup schedule.
No comments:
Post a Comment