Much like the RAID volumes that provide data redundancy and performance at the disk level, Parity Volume Sets provide redundancy for a set of files. Parity Volume Set is also called parity archive or parchive. A parity volume set uses Reed Solomon method to generate the parity volumes.
So how do the parity volume sets actually work? A typical parity volume set consists of two main things. The first thing is a PAR or PAR2 file that contains the index of the files included, their MD5 hashes, their filenames, their file sizes etc. The second thing is the actual parity volume files containing the index (PAR data) as well as parity checksums calculated using the Reed Solomon method.
Suppose you lose a file from the original file set or the original file gets corrupted. We can use the parity volume set to reconstruct the missing files or missing data easily. The redundancy of data increases with the number of the parity volume files.
If you want to create parity volume set for your important documents or files, then you can use an open-source tool called MultiPar. It is a one-window portable tool for creating the parity volume sets for your files. You have to know about parity volumes and data redundancy a little to understand what the program is doing.
Basically, you have to add your files (for which you want to create the parity volume set), setting the number of blocks (higher blocks means better data error correction), choose a folder where parity volume set is copied, choose redundancy level (higher redundancy takes more storage space) and so on.
You can click on the Preview button to see which of the files will be generated and create them. Later you can open the PAR2 file using MultiPar to verify the data and reconstruct the files if needed.
Remember MultiPar is a great tool for data verification and correction, but it is not same as having a full backup set of your files. If any of your files go missing, you may not be able to restore it because number of blocks is not enough.
You can download MultiPar from https://github.com/Yutaka-Sawada/MultiPar.