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layout doc: reformulate
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@ -94,12 +94,13 @@ follow the following recommendations:
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## Understanding unexpected layout calculations
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When adding, removing or modifying nodes in a cluster layout, sometimes
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unexpected assigntations of partitions to node can occure. These assignations
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unexpected assigntations of partitions to node can occur. These assignations
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are in fact normal and logical, given the objectives of the algorihtm. Indeed,
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**the layout algorithm prioritizes moving less data between nodes over the fact
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of achieving equal distribution of load**. This section presents two examples
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and illustrates how one can control Garage's behavior to obtain the desired
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results.
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of achieving equal distribution of load. It also tries to use all links between
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pairs of nodes in equal proportions when moving data.** This section presents
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two examples and illustrates how one can control Garage's behavior to obtain
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the desired results.
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### Example 1
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@ -266,8 +267,8 @@ This explains why node3 ends with 75% utilization (100% from before minus 25%
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that is moved to node1), and node4 ends with 25% (50% from before minus 25%
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that is moved to node1).
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This illustrates another principle of the layout computation: **if there is a
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choice in moving data out of some nodes, then all links between pairs of nodes
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are used in equal proportions** (this is approximately true, there is
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This illustrates the second principle of the layout computation: **if there is
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a choice in moving data out of some nodes, then all links between pairs of
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nodes are used in equal proportions** (this is approximately true, there is
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randomness in the algorihtm to achieve this so there might be some small
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fluctuations, as we see above).
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