sap-maxdb-halisted

# SAP MaxDB / liveCache — high availability **Source of record.** **SAP Note 952783 — *FAQ: SAP MaxDB high availability***, version **21**, released **01.11.2024**, component BC-DB-SDB **[V]** — fetched and read directly. Marks: **[V]** verified, **[G]** cited but not read in full. > **Scope note from the Note itself:** it *"describes options at database level. High availability > concepts of the hardware and the operating systems are not a subject"* — and it says plainly > *"The note is by no means complete."* **[V]** Treat the storage and OS layers as a separate > conversation with the hardware partner. **Where this still matters.** MaxDB is legacy for most NetWeaver stacks, but **liveCache** remains the engine behind SAP SCM/APO planning, and MaxDB backs **Content Server**. Hot Standby exists largely because liveCache in a mission-critical SCM scenario cannot tolerate a long restore. --- ## 1. Four mechanisms — pick by failure mode, not by sophistication MaxDB does not have one HA feature. It has four, with genuinely different properties. **[V]** | Mechanism | Automatic failover | Switch time | Protects against | Needs | |---|---|---|---|---| | **Backup / recovery** | ✗ | Restore duration | Physical **and logical** errors | Nothing extra | | **Snapshot / split mirror** | ✗ | Very fast data recovery | Logical errors, fast rollback | **Disk storage system** | | **Cluster for failover** | ✓ | Host-failover time | **Host** failure only | Cluster software, shared disk |