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Evaluation of Information Service Architectures for Grid
MDS-4 and DHT
• Hyerarchical architecure
• Flat architecture
• Created for different uses
Focus
• Information systems for grid• Metadata: resources + users• Churn• Pragmatical approach
Constraints
• Fixed schema
• Multi-attribute query
• Range query
• 3 attributes
Index list search
• The list is long• The items are geographically dispersed
Hierarchy, MDS4
• Bottleneck for performance• Collected,cached,leased data.• + slow data flow, - old data
Peer-to-peer, Multi Chord
• + good for large number of keys
• - Churn
Experiment
• Size (#nodes, #items) EGEE 250 ,25000 • Schema [CPU,RAM,Diskst] [Group,Role,Capability]
• Selectivity on whole range
TTF,TTR skewed, ρ= 0.1, 250 nodes, 120 minutes,CPU data
,00
20,00
40,00
60,00
80,00
100,00
120,00
1/MTTF
Neg
ativ
e ra
te
MDS4
p2p
MDS4 43,87 37,84 49,61 62,48 59,67 89,48 70,49
p2p 23,78 45,90 75,00 63,00 73,00 73,00 96,30
0,016 0,002 0,025 0,033 0,050 0,100 0,500
Std. Dev.
0,00
20,00
40,00
samples
SD SD MDS4
SD p2p
SDMDS4
0,20 2,38 15,00 0,80 1,70 15,00 0,50
SD p2p 25,0019,0013,00 4,70 11,0032,00 1,29
1 2 3 4 5 6 7
TTF skewed,TTR fixed, ρ= 0.1, 250 nodes, 120 minutes,CPU data
,00
20,00
40,00
60,00
80,00
100,00
1/MTTF
Neg
ativ
e ra
te
MDS4
p2p
MDS4 41,00 47,00 50,00 58,00 62,00 68,00 70,00
p2p 46,00 32,00 58,00 63,00 65,00 92,00 68,36
0,016 0,002 0,025 0,033 0,050 0,100 0,500
TTF skewed,TTR fixed, Membership data
,00
10,00
20,00
30,00
40,00
50,00
60,00
70,00
80,00
90,00
1/MTTF
Neg
ativ
e ra
te
MDS4
p2p
MDS4 43,00 45,00 50,00 59,00 74,00 70,00 71,00
p2p 40 36 37 56 78 74 83
0,016 0,002 0,025 0,033 0,050 0,100 0,500
VOMS vs CPU dataChord: voms vs cpu
0
20
40
60
80
100
1/TTF
nega
tive
rate
p2p_voms
p2p_cpu 46,00 32,00
p2p_voms 40 36 37 56 78 74 83
p2p_cpu 46,0032,00
46,00 32,00 58,00 63,00 65,00 92,00 68,36
1/TTF
MDS4: voms vs cpu
,00
20,00
40,00
60,00
80,00
1/TTF
nega
tive
rate
gt4_voms 43,00 45,00
gt4_cpu 41,00 47,00
gt4_voms 43,0045,00
43,00 45,00 50,00 59,00 74,00 70,00 71,00
gt4_cpu 41,0047,00
41,00 47,00 50,00 58,00 62,00 68,00 70,00
1/TTF
Conclusions
• MDS4, ram, slow, churn<5min,
• Much better than Chord on skewed data
• Chord multi
• Fast
• Returns fewer keys
Future
• More info available on Dynamic Behaviour of nodes?
• Increase size? / Distributed simulation platform
• Data models
• Query composition: selectivity and bias
• How coul make analysis useful to cloud /hibryd solutions?
• Any other middleware to compare?
• Relevant for DHT ?
Thank you for being here!
Environment of the experiment
Schema - CPU processor data
Attribute Unit Type Distribution
Avg. Range:min - max
CPU MHz
integer Skewed 2000
RAM MB integer uniform 100-300
Disk Storage
GB integer uniform 400-1000
Schema – membership data
Attribute Unit Type Distribution
Avg.
Range:min - max
Group ID integer
uniform NA 1-20
Role ID integer
uniform NA 1-20
Capability
ID integer
uniform NA 1-20