webMethods SAP adapter 7.1 (on-prem) uses a functionality known as ‘Centralised Transaction Store’ (CTS). This is used to coordinate SAP transaction exchange between IS cluster nodes. The CTS functionality requires one IS node to function as the SAP CTS master server, with the other being slaves. This means the master SAP adapter must be up before the other SAP adapters come up. So the IS cluster cannot be active-active.
SAP adapter 10.1 introduced ‘STS’ in addition to CTS. This uses a common filesystem mounted across all IS nodes. From webMethods SAP adapter 10.1 documentation.
To use the STS, configure all the adapters for SAP to use the same external shared directory as transaction store location. For configuration instructions, see Configuring a Shared Transaction Store.
However, mounting remote filesystems on IS instances brings reliability problems (it’s another moving part).
In webMethods.io, the ‘SAP ERP’ premium connector uses a shared MySQL database for SAP transaction coordination. This obviates the need for both STS and CTS. However, using this connector requires moving SAP integration over to webMethods.io which has disadvantages (e.g., this connector does not support ‘asynchronous ALE notifications’)
Can webMethods introduce database-backed SAP transaction coordination to the on-prem webMethods SAP adapter?
Carrying out transaction coordination using a database shared across IS nodes is the perfect architectural approach for the on-premise SAP adapter. In hindsight, the adapter should have taken this approach initially.
I’ve also filed official feature request # IS-I-245: Access rights validated