cbc28f0d15
File backed memory is enabled per Nova compute host. When enabled, host will report 'file_backed_memory_capacity' for available memory. When enabled, instances will create memory backing files in the directory specified in libvirt's qemu.conf file 'memory_backing_dir' config option. This feature is not compatible with memory overcommit, and requires 'ram_allocation_ratio' to be set to 1.0 Change-Id: I676291ec0faa1dea0bd5050ef8e3426d171de4c6 Implements: blueprint libvirt-file-backed-memory
26 lines
1.1 KiB
YAML
26 lines
1.1 KiB
YAML
---
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features:
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- |
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The libvirt driver now allows utilizing file backed memory for qemu/KVM
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virtual machines, via a new configuration attribute
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``[libvirt]/file_backed_memory``, defaulting to 0 (disabled).
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``[libvirt]/file_backed_memory`` specifies the available capacity in MiB
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for file backed memory, at the directory configured for
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``memory_backing_dir`` in libvirt's ``qemu.conf``. When enabled, the
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libvirt driver will report the configured value for the total memory
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capacity of the node, and will report used memory as the sum of all
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configured guest memory.
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Live migrations from nodes not compatible with file backed memory to nodes
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with file backed memory is not allowed, and will result in an error. It's
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recommended to upgrade all nodes before enabling file backed memory.
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Note that file backed memory is not compatible with hugepages, and is not
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compatible with memory overcommit. If file backed memory is enabled,
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``ram_allocation_ratio`` must be configured to ``1.0``
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For more details, see the admin guide documentation:
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https://docs.openstack.org/nova/latest/admin/file-backed-memory.html
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