Comment 3 for bug 1804239

Hello guys, I've found a possible scenario that may be slowing down requests in a dhss=true environment.

When running with dhss=true, the share manager will try to fetch the pools for each share server [0], calling the function get_share_server_pools(share_server) [1] in driver responsible for gathering only the pools associated to the specific share server.

The NetApp cDOT driver always associates all pools to all vservers, so it just ignores the share server parameter and instead returns information about all pools. If your environment have many share servers created, the driver will repeatedly request the same information to the storage what looks totally unnecessary.

Caching pools data periodically and retrieving just the cached information to the manager would probably improve driver performance for a multi share server environment.

[0] https://github.com/openstack/manila/blob/10bb9e8efc3b2c8c8c2d6168d1e215fb354b355e/manila/share/manager.py#L3571
[1] https://github.com/openstack/manila/blob/10bb9e8efc3b2c8c8c2d6168d1e215fb354b355e/manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py#L300