Add ALUA (Asymmetric Logical Unit Access) support to the iSCSI target,
enabling dm-multipath on Linux to automatically detect path state changes
and reroute I/O during HA failover without initiator-side intervention.
- ALUAProvider interface with implicit ALUA (TPGS=0x01)
- INQUIRY byte 5 TPGS bits, VPD 0x83 with NAA+TPG+RTP descriptors
- REPORT TARGET PORT GROUPS handler (MAINTENANCE IN SA=0x0A)
- MAINTENANCE OUT rejection (implicit-only, no SET TPG)
- Standby write rejection (NOT_READY ASC=04h ASCQ=0Bh)
- RoleNone maps to Active/Optimized (standalone single-node compatibility)
- NAA-6 device identifier derived from volume UUID
- -tpg-id flag with [1,65535] validation
- dm-multipath config + setup script (group_by_tpg, ALUA prio)
- 12 unit tests + 16 QA adversarial tests + 4 integration tests
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
