Changes between Version 32 and Version 33 of VDEchp


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Timestamp:
10/10/11 01:12:54 (13 years ago)
Author:
lvpeng
Comment:

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  • VDEchp

    v32 v33  
    2828To compose a globally consistent state of all the VMs, the checkpoint of each VM must be coordinated. Besides checkpointing each VM’s correct state, it’s also essential to guarantee the consistency of all communication states within the virtual network. In Figure 2, the messages exchanged among the VMs are marked by arrows going from the sender to the receiver. The execution line of the VMs is separated by their corresponding checkpoints. The upper part of each checkpoint corresponds to the state before the checkpoint and the lower part of each checkpoint corresponds to the state after the checkpoint. A global checkpoint (consistent or not) is marked as the “cut” line, which separates each VM’s timeline into two parts. We label the messages exchanged in the virtual network into three categories:
    2929
    30 (1) The state of the message’s source and the destination are on the same side of the cut line. For example, in Figure 2, both the source state and the destination state of message m,,1,, are above the cut line. Similarly, both the source state and the destination state of message m,,2,, are under the cut line.
     30 * (1) The state of the message’s source and the destination are on the same side of the cut line. For example, in Figure 2, both the source state and the destination state of message m,,1,, are above the cut line. Similarly, both the source state and the destination state of message m,,2,, are under the cut line.
    3131
    3232(2) The message’s source state is above the cut line while the destination state is under the cut line, like message m,,3,,.