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Algorithm 4.2
Step 1: [index service pulls information]
The index service pulls host environments information of all failure detec-
tors with the round-robin algorithm, and system information includes
static and dynamic information.
Step 2: [compute SL i of all hosts]
Compute service level of host environments as
a+b
FR
Mem
SL
=
i
i
(4.11)
i
Load
i
and take the host i which has Max( SL i ). FR i is the frequency of CPU i , Mem i
is the memory of host i and Load i is the load of host i ; a and b are
coefi cients.
Step 3: [i nd a group leader on the specii c host]
Get the list of failure detectors on host i , which is chosen in step 2. If one
of them is a group leader, go to step 6.
Step 4: [deploy a new local group leader on the specii c host]
Deploy a group leader failure detector on host i , and all the failure detectors
in this group send detection messages to this failure detector.
Step 5: [global notii cation about the local leader]
The index service sends a trigger message to upper-level failure detector
to tell the new local group leader, and the new group leader sends detection
messages to the upper-level failure detector.
Step 6: [handle the new monitored objects]
If there are new monitored objects added in, i rst try to i nd the lightest-
load failure detector in this group by getting the Min( N fdi ). If Min( N fdi ) is
less than F s
1, then the new object sends “I'm alive” message to this
failure detector; go to step 8.
Step 7: [deploy a new failure detector]
Create one more failure detector, and the new coming object sends “I'm
alive” to this failure detector. If the number of failure detectors is larger
than S g , add a new group with a group leader failure detector and this
new group leader registers itself to the upper-level failure detector.
Step 8: [change the messages sent to the upper-level failure detector]
Change the message list sent to the upper-level failure detector with the
new object; at the same time send a message to index service to notify the
global change.
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