Traditional Backup, BackupMaster and Synchronisation
Traditional backup is generally performed using a tape
based backup system with software providing the control. Whilst there
have been significant advancements in tape technology over the years it
is still a relatively slow process and has particular weaknesses when
it comes to useful life of the tapes, time taken to backup and restore
and the integrity of the data.
Backing up a large system can be slow using tape
backup, as data is stored sequentially along the length of the tape.
This means that if you need to restore a document that has been saved
at the end of the tape you need to wind the tape forward to the
relevant point before being able to restore the file. On large systems
this can take over half an hour to an hour to complete.
To try and speed up tape backup, systems managers use
various techniques such as the incremental backup method to back up
their systems. Incremental backup means that only files that have
changed since the last backup are backed up to tape thereby reducing
the amount of data transferred to tape. This reduces the time taken to
backup, however if things go wrong and you need to restore, then the
user must go back to the last 'full' backup and re-install all of the
incremental tapes in order. This can be very time consuming assuming
all of the tapes are available and can be re-read and be restored. So
backing up can be speeded up on tapes but restoring can take quite a
while.
BackupMaster is much faster and more reliable than tape
backup as it will backup to a flash drive or external hard disk drive,
thus speeding up the backup process. BackupMaster uses an enhanced
search algorithm to search for files to backup speeding up the backup
process. Restoring is very quick too as you simply list and select the
files or folders that you want to restore and restore them at the click
of a button. There is no searching thorough the length of a tape and no
incremental restore needed.
BackupMaster scans the whole of all the hard drives
selected when doing a backup. BackupMaster preserves the directory tree
and compresses and encrypts individual files as they are backed up.
BackupMaster looks at each file in turn to ensure it is the latest
version, if it is it backups the file up and verifies that the file can
be reopened by the restore procedure. This means that BackupMaster is
many times faster than traditional tape backup and data is stored in
the same directory structure as on the PC.
One of the main drawbacks of tape backup is the
reliability of the tapes themselves. Tapes are quite delicate and
susceptible to heat and physical damage etc. Many establishments use
the same tapes year in year out without checking that the tapes are
still readable. It is only when they try to restore after a problem
that they find out if the data can be salvaged, it's too late if it
can't be restored. BackupMaster on the other hand checks and verifies
that the data is readable when it backs up to an external device
ensuring data can be restored.
The flash drives and external hard drives used are
designed to be robust and will keep data valid for up to 10 years. They
are much faster than tape backup systems and CD RW systems. Plus given
that BackupMaster has a low process overhead it won't take over your PC
when completing a full backup enabling you to do other work if you wish.
True backup versus Synchronisation
There are broadly speaking two methods of creating a
backup, one is synchronisation and the other is true backup. The two
methods are subtly different and have potential consequences for users
and so choice of the appropriate method is essential.
Many backup systems use a process of file
synchronisation to carry out backups. Synchronisation has its main use
when a user works on more than one station to do their work and may
swap use between a laptop and a networked PC for example. To
synchronise you need a 'central' store where data is stored and a local
store on one or more machines where files are worked on. When the
software synchronises it checks for the latest working copy (usually on
a laptop or PC) and checks the version and date stamp of the file. It
then compares this with the file in the 'central' store, if that file
is 'newer' than the file in the central store it will synchronise
(backup) the file to the 'central' store overwriting the older file.
This is fine however if the algorithm being used to
compare files is good enough to manage the different versions and
resolve conflicts automatically. In many cases the software is unable
to manage the different versions and rely on the user to resolve
conflicts in versions manually. This can be very time consuming if
there are many files to resolve.
For example, one problem that can arise with
synchronisation is if a document is deleted from one system/folder by
accident. In many cases the synchronisation software will spot that the
file has been deleted from the working station and delete it from the
'central' store when synchronisation is next done. This can lead to
data being inadvertently deleted with little or no chance to restore
the file, which defeats the objective of safe backup.
BackupMaster doesn't use synchronisation as a full
backup is made each time. That is BackupMaster will scan every file on
the selected hard drives or network drives and check if it the latest
version. If it is the latest version the file it is backed up to the
external drive overwriting the older version. This speeds up the backup
process as only files that have changed are backed up. However, if a
file is deleted from the PC, BackupMaster will not delete the
corresponding file from the backup set. This means that if the user
wants to restore the file at a later date it will be available, even if
they have deleted the file accidentally from their PC. The files will
remain on the BackupMaster device until the user deletes the files from
the device. This is different from an incremental or differential
backup as all data is stored once in the exact file structure that
appeared on the drive. This means we don't need to restore each partial
or incremental backup to get our files back, we simply select the file
or folder we want restoring and this is done at the push of a button.
To provide a solution for people with more than one PC to backup we have developed the BackupMaster MultiBackup
solution, which enables the user to backup more than one PC to the same
device. Each backup is kept separate from the others and the system
'knows' which backup set belongs to which PC. If a PC is damaged,
stolen or lost then with BackupMaster it is easy to restore everything
back in the correct directories very quickly. On MultiBackup the
correct files for the lost PC will be restored to the new PC of your
choice. Restoring is secure, as the files can't be restored without the
unique restore code, which is unique to each device.
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