Revision 325947e7 man/hbal.rst
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- a node to go into N+1 failure state |
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- an instance to move onto an offline node (offline nodes are either |
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read from the cluster or declared with *-O*) |
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read from the cluster or declared with *-O*; drained nodes are |
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considered offline) |
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- an exclusion-tag based conflict (exclusion tags are read from the |
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cluster and/or defined via the *\--exclusion-tags* option) |
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- a max vcpu/pcpu ratio to be exceeded (configured via *\--max-cpu*) |
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~~~~~~~~~~~~~~~ |
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As said before, the algorithm tries to minimise the cluster score at |
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each step. Currently this score is computed as a sum of the following
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components: |
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each step. Currently this score is computed as a weighted sum of the
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following components:
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- standard deviation of the percent of free memory |
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- standard deviation of the percent of reserved memory |
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- standard deviation of the percent of free disk |
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- count of nodes failing N+1 check |
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- count of instances living (either as primary or secondary) on |
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offline nodes |
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offline nodes; in the sense of hbal (and the other htools) drained |
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nodes are considered offline |
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- count of instances living (as primary) on offline nodes; this |
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differs from the above metric by helping failover of such instances |
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in 2-node clusters |
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