SCSI multipath device handlers (ALUA, RDAC, EMC CLARiiON, HP MSA)
Helper modules that let the Linux SCSI layer talk correctly to enterprise storage arrays reached over multiple paths, handling per-vendor quirks for failover and path selection. They cover the modern standards-based ALUA protocol used by most current SANs as well as older vendor-specific schemes from EMC CLARiiON, NetApp/LSI RDAC arrays, and HP/Compaq active-passive MSA boxes.
recommendation
Worth keeping but worth flagging the mix inside. The ALUA handler is actively maintained, with 2025-2026 patches from Oracle, SUSE, and Pure Storage refactoring it toward a shared core, and Red Hat still documents all four handlers in current RHEL 10 multipath guidance against arrays like NetApp E-Series that ship today. The vendor-specific hp_sw, emc, and rdac pieces are the legacy tail and would benefit from a note that they exist for older arrays while ALUA is the path forward.
repository signals
sources
- lore.kernel.org
March 2026 linux-scsi patch series proposed creating a core ALUA driver and touched scsi_dh_alua heavily, showing active upstream evolution rather than abandonment.
- lore.kernel.org
April 2026 linux-scsi patch from Pure Storage adjusted ALUA timeout handling, indicating current vendor use and testing of the ALUA handler.
- docs.redhat.com
Current RHEL 10 multipath documentation still documents the emc, rdac, hp_sw, and alua hardware handlers, and notes kernels auto-attach handlers for known devices including SCSI-3 ALUA.
- docs.netapp.com
NetApp still publishes current E-Series storage-family documentation, supporting that at least the RDAC-targeted family remains a live product line.
codex reasoning notes (technical)
`exec_command` inspection of local Kconfig/source showed this is a real SCSI device-handler driver directory covering ALUA, RDAC, EMC CLARiiON, and HP/COMPAQ active-passive arrays. `lore_activity` on scsi_dh_alua.c returned multiple 2025-2026 linux-scsi patches from Oracle, SUSE, and Pure Storage, including refactoring toward a core ALUA implementation, which is strong keep evidence and not removal talk. `web.search_query` found current RHEL 10 docs still documenting these handlers and current NetApp E-Series docs, so the directory still maps to deployed enterprise SAN hardware; annotate because ALUA is clearly current but hp_sw/emc/rdac are more legacy vendor-specific tails within the same directory.