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Table 15.1 Total overhead in studied algorithms
Algorithms
Total Overhead
Redundant Data Regeneration
B + ( h 1)( B / ( N h ))
Regeneration by archive server
B / ( N h ) + ( h 1)( B / ( N h ))
+
Sequential Redundant Data Update (SRDU)
Block movement under SRDU
( h
1)( B /
( N h ))
Required data blocks are sent to r 0
d N h 1
. . .
. . .
d 0
d 1
r 0
r 1
r h 1
p 1
p h - 1
r 0 computes its own redundant data and
partial results p j for other redundant nodes.
Figure 15.17 Update of multiple redundant nodes in SRDU
50000
Regeneration by Redundant Node
40000
30000
20000
SRDU
10000
Regeneration by Archive Server
0
0
5
10
15
20
25
30
35
40
Number of Redundant Nodes
Figure 15.18 Redundant data update overhead versus redundant node size
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