TIME SYNCHRONIZATION IN CLUSTER SYSTEMS
First Claim
1. A computer-implemented method comprising:
- sending, toward a master node, a first message that indicates a first time at which the first message is sent toward the master node, as determined based on a local clock of a particular node that sends the first message;
receiving, from the master node, a second message that indicates a second time at which the master node received the first message, as determined based on a master clock of the master node;
based on at least the first time, the second time, and a third time at which the second message was received from the master node, as determined based on the local clock, adjusting a setting of the local clock to follow more closely a setting of the master clock.
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Abstract
Techniques are described herein for synchronizing cluster time. According to one technique, a master node is appointed in a cluster. Other “slave” nodes periodically synchronize their clocks with the master node. To synchronize its clock with the master node, a slave node sends a timestamped message to the master node, which also timestamps the message and sends the message back to the slave node, which then timestamps the message again. Based on the timestamps, the slave node is able to determine the difference between the master node'"'"'s clock'"'"'s time and slave node'"'"'s clock'"'"'s time, compensating for the message travel time between master node and slave node. Depending on various circumstances, and based on the determined difference, the slave node adjusts its clock so that the time indicated by the slave node'"'"'s clock at least begins to approach more closely the time indicated by the master node'"'"'s clock.
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Citations
26 Claims
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1. A computer-implemented method comprising:
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sending, toward a master node, a first message that indicates a first time at which the first message is sent toward the master node, as determined based on a local clock of a particular node that sends the first message; receiving, from the master node, a second message that indicates a second time at which the master node received the first message, as determined based on a master clock of the master node; based on at least the first time, the second time, and a third time at which the second message was received from the master node, as determined based on the local clock, adjusting a setting of the local clock to follow more closely a setting of the master clock. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A volatile or non-volatile computer-readable storage medium on which are encoded instructions which, when executed by one or more processors, cause the one or more processors to perform steps comprising:
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sending, toward a master node, a first message that indicates a first time at which the first message is sent toward the master node, as determined based on a local clock of a particular node that sends the first message; receiving, from the master node, a second message that indicates a second time at which the master node received the first message, as determined based on a master clock of the master node; based on at least the first time, the second time, and a third time at which the second message was received from the master node, as determined based on the local clock, adjusting a setting of the local clock to follow more closely a setting of the master clock. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification