Tam Chantem, Philip Little and Faruck Morcos. iDIBS : Reliable and Efficient Distributed Backup. Improving Peer-to-Peer Backup Systems. Objective : Improve peer-to-peer backup techniques. Approach : Built on DIBS , an existing peer-to-peer backup system. Results : Improved 3 aspects of DIBS:
Assume: Peers = 4 K = 5 N = 6
So, N = 8
LT codes vs. RS codes
Processing Time (sec)
File Size (Kb)
LT codes are:
1. Faster than RS
2. Flexible performance
1. Allow faster recovery.
2. Increase reliability.
LT codes are probabilistic.
As T > 256 decoding is less stable
LT need a minimum of 15% of extra overhead + ESI to decode.
Peer lists induce a small amount of overheadThe iDIBS tradeoff
We contributed to the improvement of DIBS in the following ways:
If: Peers > K then N = K + 1;else: PiecesPerPeer = 1;while PiecesPerPeer * (Peers - 1) < K do: PiecesPerPeer = PiecesPerPeer + 1; N = N * K;end if
If a peer is offline, recovery is still possible