| Virtualization technology,which has been widely used,can fully utilize the storage and computing resources of physical server.However,migrating applications and data from physical server to virtualization platform is still challenging.Traditionally,this procedure requires suspending service for a long time,which is undesirable.In addition,the migrated applications and data are probably unavailable due to hardware dependency or lack of data integrity checking.Therefore,it is motivated to design an online migration on storage virtualizing for ensuring data and application availability without suspending service.In this paper,we propose online migration on storage virtualizing,design and implement online migration system,which includes data access module and data migration module.The data access module provides transparent data accessing mechanism for user by automatically redirecting data access request from foreground applications to local physical server or remote virtualization platform using a mapping table.The data migration module migrates data in the unite of files,and it utilizes three migration mechanisms as balancing migration mechanism,suspending migration mechanism and rapid migration mechanism.By switching between the three migration mechanisms,the data migration module is capable of migrate data fast without degrading the quality-of-service to users.We also design three methods,i.e.,wait-before-write,segment suspending,and copy-on-write,for guaranteeing the data-consistency when migrating data without suspending the service.Finally,we build a prototype system upon FUSE and evaluate its performance by using Filebench Benchmark.Experimental results show that read and write latencies increase less than 10 milliseconds when balancing migration mechanism is processing.On the other hand,under the rapid migration mechanism,migration throughput is up to 98MB/s,which is close to the limited bandwidth of the tested platform. |
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