Install Parchive

[tafkap]

Hi all,

 

i would like to install Parchive software, i can get DBM archive or DEB archive or source .GZ.

 

Is it possible to install it on unRAID server and how ? (noob on UNIX)

 

Thanks a lot.

 

http://parchive.sourceforge.net/#clients

[Billped]

Isn't that redundant?  Parity archiving on a parity system?

 

 

Bill

[tafkap]

Not redundant, Parchive is used for repair the corrupted archive files.

[montery]

Ummm..... yes, it's redundant.

 

Parchive works by taking a file (or series of files) and chunking it up into smaller pieces.  Then it calculates parity data across those pieces and stores this data in separate files. 

 

On the internet, there used to be a popular method of transferring files around back in the mid-90's using the newsgroups (check out google newsgroups for a sample of what's there).  People would UUencode their files, send them as messages to the newsgroup, and other people would pull these messages down, knit together the messages, and voila!  Software!  Or, in the case of the newsgroups, typically it was porn, but whatever.

 

There was a slight problem to this otherwise efficient approach.  The underlying architecture of the newsgroup meant that files (spread across many messages) are sent on a store-and-forward basis by individual computers that participated in the newsgroups.  Because of this store-and-forward method of spreading the goodness, not every system had the same amount of drive space to dedicate to the newsgroups.  So old messages didn't stay long, and in some cases, if disk space was low, admin's would not do the "forward" part of store and forward.   The end result was that you would see missing parts out of a multi-part series.

 

How does Parchive solve this?  If you lost a part of your data you could recover so long as you had the parity files.  Depending on how much of the archive you've already downloaded, you may not need all of the parity files.  It's pretty cool software and I was initially toying with the idea of using Parchive instead of Raid-5.  Then I found unraid.

 

Unraid works on the same principle as Parchive -- in fact, I would be surprised if it didn't use the same mathematical algorithm to compute the parity bits (google Reed-Solomon).  Unraid takes your data on all your drives, and breaks it logically into chunks.  Each chunk is then (essentially) added up to a binary 1 or 0 value.  The parity bit is also added so that all the data across all the chunks is the same (either all zeros or all ones).  This parity info is then written to the parity drive, and consulted on read from the data drive (to ensure accuracy) and re-calculated on writes.

 

So, Parchive isn't buying you anything since unRAID does it for you!