ISCSI Transparent Reliable Multicast Based On Similar Payload

Under the Network-computing mode, the computing tasks are submited to the various distributed computing resources and data are storied focused on an on-demand deployment storage equipment or system, the system data saved in the storage resources is no longer belong to a particular computing entity which can be shared by all network resources.The iSCSI (internet SCSI) protocol combines the advantage of SCSI and TCP/IP protocol, so it is the first choice for network storage.The paper studied the I/O load characteristics of iSCSI network computing system, combined these features and proposed an I/O acceleration strategy under the network computing system:Trasnparent reliable multicast based on similar payload.At first, through the creation of iSCSI network computing system, established the access mode of I/O requests then proposed the concepts of similar payload, similar blocks, also implemented an algorithm for detecting similar blocks. Second, extended the traditional architecture of iSCSI protocol, introduced reliable multicast protocol into iSCSI session, and patched up weakness of TCP unicast transparent model in iSCSI session. Expanded the definition of iSCSI PDU, so that iSCSI session can comprehend iSCSI multicast session announcement and transfer the similar block by multicast. Based on similar pyload, the paper proposed a new cache page replacement algorithm. And also studied the retransmission of lost data, multicast session is transmitted by iSCSI session, so that the reliability of multicast session is guaranteed. At last, the experiment tests show that, the introduction of reliable multicast protocol could improve the system's expansion, when I/O conditions of a relatively high degree of concurrency, transparent reliable protocol can improve the guest OS boot times and application load.