As the demand for high volume transaction processing grows, coupling multiple computing nodes becomes increasingly attractive. This paper presents a comparison on the resilience of the performance to system dynamics of three architectures for transaction processing. In the shared nothing (SN) architecture, neither disks nor memory is shared. In the shared disk (SD) architecture, all disks are accessible to all nodes while in the shared intermediate memory (SIM) architecture, a shared intermediate level of memory is introduced. A transaction processing system needs to be configured with enough capacity to cope with the dynamic variation of load or with a node failure. Three specific scenarios are considered: 1) a sudden surge in load of one transaction class, 2) varying transaction rates for all transaction classes, and 3) failure of a single processing node. We find that the different architectures require different amounts of capacity to be reserved to cope with these dynamic situations. We further show that the data sharing architecture, especially in the case with shared intermediate memory, is more resilient to system dynamics and requires far less contingency capacity compared to the SN architecture.
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