Problem
In multi-gateway Ceph NVMe-oF deployments operating at scale (e.g., 100+ subsystems, 8 gateways so 8 ANA groups per gateway ), setting or updating ANA states triggers an excessive number of JSON-RPC requests over the management socket to SPDK.
Currently, ANA states are updated on a per-subsystem, per-ANA-group basis. As a result, changing ANA states across 100 subsystems and 8 ANA groups requires 800 individual JSON-RPC invocations per failover/fencing event.
Impact & Bottlenecks
Severe Management Socket Overhead: Executing hundreds/thousands of sequential JSON-RPC calls introduces significant Unix domain socket context switches, JSON serialization/parsing overhead, and round-trip IPC delays.
Failover Timeout Risk: The IPC processing time alone can take 1 to 2+ seconds, consuming a massive portion of the time-sensitive failover window and increasing the risk of host NVMe io_timeout expirations.
Proposed Solution
Introduce a Batch SPDK RPC API:
Add a single batch RPC (e.g., nvmf_set_ana_states_all_subsystems) that accepts an array or map of ANA groups and target states in a single JSON-RPC payload.
Optimizations:
Inside the C implementation of the batch handler, check the current state against the requested state before initiating a transition
Iterate through all target subsystems internally in C memory during a single socket invocation
Problem
In multi-gateway Ceph NVMe-oF deployments operating at scale (e.g., 100+ subsystems, 8 gateways so 8 ANA groups per gateway ), setting or updating ANA states triggers an excessive number of JSON-RPC requests over the management socket to SPDK.
Currently, ANA states are updated on a per-subsystem, per-ANA-group basis. As a result, changing ANA states across 100 subsystems and 8 ANA groups requires 800 individual JSON-RPC invocations per failover/fencing event.
Impact & Bottlenecks
Severe Management Socket Overhead: Executing hundreds/thousands of sequential JSON-RPC calls introduces significant Unix domain socket context switches, JSON serialization/parsing overhead, and round-trip IPC delays.
Failover Timeout Risk: The IPC processing time alone can take 1 to 2+ seconds, consuming a massive portion of the time-sensitive failover window and increasing the risk of host NVMe io_timeout expirations.
Proposed Solution
Introduce a Batch SPDK RPC API:
Add a single batch RPC (e.g., nvmf_set_ana_states_all_subsystems) that accepts an array or map of ANA groups and target states in a single JSON-RPC payload.
Optimizations:
Inside the C implementation of the batch handler, check the current state against the requested state before initiating a transition
Iterate through all target subsystems internally in C memory during a single socket invocation