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Architecture and Design description

DB Changes

There are no db changes for the feature.

Registering zone wide primary storage

• CreateStoragePool api issued with scope as 'zone' and hypervisor type as 'Hyperv'
• Storage pool entry is persisted in the database.
• A ModifyStoragePoolCommand is send to all up and enabled Hyper-V hosts in the zone.
• The host makes a note and persists the zone wide primary storage path in its configuration file.
• On success, the zone wide storage pool state is marked as 'Up' in the database.
• Whenever a new host is added to the zone, ModifyStoragePoolCommand is send to the new host too.

Storage allocation

• When a volume is created, cloudstack queries all the storage allocators for a suitable pool for the volume. It checks with the allocator storage allocators for a suitable pool for the volume in the following order; local, cluster and finally zone wide storage allocator.
• If a suitable pool is found by any of the allocators; then that pool the volume is placed on that pool.
• If a volume is created with a 'Shared' disk offering and a cluster wide and a zone wide pool, both a re are available; the volume may get placed in either of the pools.
• To guarantee placement of a volume on a zone wide primary storage; storage tags may be used.

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