Have you stopped to examine the kind of compression technology that is being used by your online backup vendor? Most of us take it for granted that our backup vendor knows just what needs to be done and would use technology that will safeguard our data. While faith is essential, it is necessary to repose trust only when you know fully well what you are letting yourself in for!
Blind faith may result in disaster. Look around you, and you can find any number of organizations that come to grief because they trust the software to compress their data without corrupting it and found that they are unable to recover their data because the compression process has corrupted it!
So, let us begin at the beginning. What is compression? How does it compress data for saving on storage? The understanding will help you appreciate what can go wrong during a compression process.
Compression systems use source coding or bit rate reduction process to encode information using fewer bits than the original representation of data. It is useful for reducing consumption of expensive resources such as hard disk space or bandwidth.
But, all compression systems cannot work on all kinds of applications! The compression system that is used on video cannot obviously be used with texts. The use will be detrimental to the “file” being compressed and it may become impossible to decompress it at a later stage using the same or even similar decompression technologies! You may further require the video to stream as it decompresses, so that it does not consume space on your hard disk during run time.
So, the design of compression systems are complicated and involves trade offs of various factors, such as type of compression, degree of compression, the amount of distortion that can be introduced and the computational resources required for compressing or decompressing the data.
Content compression can be as simple as removing all the spaces between words or inserting a single repeat character to indicate a string of repeated characters. Sometimes, smaller bit strings may be substituted for frequently recurring characters. This type of compression can reduce text by 50%.
Graphic compression can be lossless or lossy. Lossless compression allows all information to be restored during decompression. Lossy compression results in loss of information during compression and consequently the information cannot be restored during decompression.
So, find out what kind of compression technology your backup vendor is using for different kinds of “files” that you may be uploading to your backup server. It is better to be safe than sorry.