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The SAP HANA nodes connect to the SC Series arrays through an FC SAN. SAN components require, at a minimum, 8 Gb/s link speed, and the SAN topology must follow best practices for redundant components and links.
The SAN connectivity, which includes host bus adapters (HBAs), SAN ports, switches, and array front-end ports, requires careful planning. The SC Series technology provides multiple options for front-end connectivity through on-board ports directly on SC Series controllers and also on optional I/O modules whose configuration must match between storage processors (SPs). FC I/O module ports use 16 Gb small form-factor pluggables (SFPs). We recommend 16 Gb FC for the best performance. All FC ports can negotiate to lower speeds.
The SAP HANA KPIs for TDI deployments require a maximum bandwidth of 400 MB/s per SAP HANA node. If, for example, ten nodes are connected in a SAN to an SC Series array, a total bandwidth of 4,000 MB/s is required. Assuming a 16 Gb/s front-end port provides approximately 1,500 MB/s bandwidth, we recommend at least six dedicated 16 Gb/s front-end ports to support ten SAP HANA nodes—three on each storage controller (3 x 1,500 MB/s = 4,500 MB/s) to facilitate HA, load balancing, and continued connectivity in the event of SP failure.
While this bandwidth requirement applies only in the unlikely event that all nodes simultaneously demand all available bandwidth, SAP HANA certification criteria require that the storage arrays sustain this peak workload.
This requirement does not only affect the storage front-end configuration. In the example of ten nodes, the complete path through the SAN network must also be configured to support the required bandwidth.
Each HBA port (initiator) creates a path for I/Os between the host and the SAN switch, which then continues to the SC Series storage. If a host uses only a single HBA port, it has a single I/O path that serves all I/Os. Such a design is not advisable. A single path does not provide HA and risks a potential bottleneck during high I/O activity due to the lack of additional ports for load balancing.
A better design provides each SAP HANA server with at least two HBA ports, preferably on two separate HBAs. The additional ports provide more connectivity and enable native Linux DM-Multipathing (DM-MPIO) to load balance and fail over across HBA paths.
The SC Series is a block array with simultaneous multiprotocols (iSCSI + FC or iSCSI + SAS) that are supported differently as front-end network protocols depending on the SC model. SC Series arrays use FC for SAP HANA persistence (data and log).
The number of available PCI slots varies among SC Series models as I/O modules. FC-16 and FC-32 HBA availability also varies among different SC Series arrays.
Each SAP HANA node must connect to a minimum of two FC ports on each storage controller. For illustration purposes, the following figure shows the recommended FC port connectivity on an FC HBA on each SC7020 controller.
Note: SC5020 and SCv3020 arrays have one PCI-E slot, which can be used for FC, iSCSI, or SAS I/O cards. SC9000 and SC7020 models have more PCI-E slots for scalability on storage array front-end and back-end I/O cards.
To achieve full I/O performance for SAP HANA production deployments, implement the following FC port requirements for an SC Series array: