nova/releasenotes/notes/default-host-numa-strategy-to-spread-18668c6d80154042.yaml
Sean Mooney e76ec7af4d update default numa allocation strategy
This change updated the default of
[compute]/packing_host_numa_cells_allocation_strategy
to False making nova spread vms across numa nodes by defualt.

This should significantly improve scheduling performace
when there are a large number of host and guest numa node
and non empty hosts. see bug 1978372 for details.

Related-Bug: #1978372
Change-Id: I6fcd2c6b58dd36674be57eee70894ce04335955a
2022-08-10 15:45:10 +01:00

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YAML

---
upgrade:
- |
During the triage of https://bugs.launchpad.net/nova/+bug/1978372
we compared the performance of nova's numa allocations strategies
as it applied to the large numbers of host and guest numa nodes.
Prior to ``Xena`` nova only supported a linear packing strategy.
In ``Xena`` ``[compute]/packing_host_numa_cells_allocation_strategy``
was introduced maintaining the previous packing behavior by default.
The numa allocation strategy has now been defaulted to spread.
The old behavior can be restored by defining:
``[compute]/packing_host_numa_cells_allocation_strategy=true``