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In-Depth Information
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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