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Transcript of Disk Array Performance Estimation AGH University of Science and Technology Department of Computer...
Disk Array Performance Estimation
AGH University of Science and TechnologyDepartment of Computer Science
Jacek Marmuszewski
Darin Nikołow, Marek Pogoda, Renata Slota, Jacek Kitowski
Outline Introduction
motivation for performance estimation of disk array
problems connected with estimation of disk array
requirements for disk array estimator
Solution
Environment
Disk Array Performance Tests
Estimation Model
Estimation Quality Tests
Future work
Introductionmotivation for performance estimation of disk array
Proper and efficient performance estimation of storage systems is essential for many processes occurring in distributed computational environments such as:
replica selection,
new replica creation,
creating VO specifying data storage performance
requirements in SLA,
guarantying the fulfillment of SLA within VO.
Introductionproblems connected with estimation of disk array
Complexity of algorithms used to determine best solution for storing data
Shared resources
Virtualization
Introductionrequirements for disk array estimator
Estimator response time Estimator response time Estimation quality
Solution
Model identification via active experiments
Environmentgeneral view
- Disk Array - Host / Server - User / Application
Test Environment
Disk Array 1
Infortrend A16F-G2430
2GB cache
16x 1TB HDD – SATA, RAID6
2x 4/8 Gbit/s fiber channel interface
Server 1
Xeon QuadCore
4GB RAM
Disk Array 2
Intel Entery Storage System SS4200-E
4 x 500GB HDD - SATA
RAID5
1 Gbit Ethernet
Server 2
Intel Core2Duo E4400 2.0Ghz
2GB RAM
Test Environment
- Disk Array - Host / Server
Monitoring daemon
Monitoring daemon
Monitoring daemon
Estimator Service & database
Sending data using ICE
ICE – Internet Communication Engine form ZeroC
Disk Array Performance Tests
Tests written in C
Using 'fwrite'
Synchronizing (flushing) once – before ending test
usu
Disk Array Performance Tests
Disk Array Performance Tests
Model
How to obtain those values automatically ?
Model
size
speed
- stored in cache
- stored on HDDs
Cache size
Model
Cache usage estimation
Monitoring i/o operation on every host!
Knowledge of NIC speed and HDDs speed
Best way : Get this information directly form Disk Array
Model
Multiple users – average bandwidth usage
Divide bandwidth equally to all hosts
On host, divide bandwidth equally to all users
If host/user in not using its all bandwidth divide it to others
Use this value as „Max Disk Array Speed”
Do the same for „Max HDD's speed” value
Model
Multiple users – estimating future r/w speed
Don't use current speed!
Use weighted mean for statistical r/w data.
History time History time
speedspeed
time time
s0 s1 s2 s3 s0 s1 s2 s3
AvgSpeed=1*s0 + 2*s1 + 4*s2 + 8*s3
15 AvgSpeed=∑i=0
2 i∗si
∑i=0
2 i
Estimation quality tests
Estimation quality tests
Estimation quality testsfor multiple users
Estimation quality testsfor multiple users
Estimation quality testsfor multiple users
Average absolute performance estimation error: 34,8 MB/s
Maximal absolute performance estimation error: 64,4 MB/s
Average absolute performance estimation error: 8,2 %
Maximal absolute performance estimation error: 13,9 %
Average estimator response time (+ ICE) = ~1.2ms
ICE – Internet Communication Engine form ZeroC
Summary and Future Works
Collecting more data directly form Disk Array administration / diagnostic tools
Analyzing more data – searching for patterns in Disk Array usage.
Thank You