sap-db2-hadrlisted

# Db2 for LUW — HADR under SAP **Source of record.** **SAP Note 1612105 — *DB6: FAQ on Db2 High Availability Disaster Recovery (HADR)***, version **6**, released **17.06.2025**, component BC-DB-DB6 **[V]** — fetched and read directly. Marks: **[V]** verified, **[G]** cited but not read in full. > **This skill is the SAP layer, not a Db2 tutorial.** Note 1612105 says so itself: *"This SAP Note > is not an introduction to Db2 HADR. Read the IBM documentation first."* What follows is what > changes **because it is SAP** — client connectivity, non-logged operations, maintenance procedures. --- ## 1. Synchronization modes `HADR_SYNCMODE` takes one of four values. **[G — IBM]** | Mode | Primary commits after logs are… | |---|---| | `SYNC` | written to disk on **both** primary and standby | | `NEARSYNC` | written to disk on primary **and received into memory** on standby | | `ASYNC` | written to local disk **and sent** to standby | | `SUPERASYNC` | *(no wait — primary never blocks on replication)* | `NEARSYNC` is the usual production choice: near-zero data loss without paying for the standby's disk write in the commit path. > **Multiple standbys change the mode silently.** With more than one standby, the configured > `HADR_SYNCMODE` applies **only to the first (principal) standby** in `HADR_TARGET_LIST`. > **Auxiliary standbys are `SUPERASYNC`** regardless of what you set. **[G]** Do not promise > a customer NEARSYNC protection on standby #2 and #3. **Standby count is versi