Home > Workload Solutions > SAP > Guides > SAP HANA TDI Guides > Dell Validated Design for SAP HANA TDI with Dell PowerStore Storage > Storage resources
All block storage resources in a PowerStore system have a defined performance policy, which is set to medium, by default. The policy does not affect system behavior unless some volumes are set to low performance while other volumes are set to medium or high performance. Reserve the low-performance setting for volumes with fewer critical performance needs and use the high-performance setting for all SAP HANA persistence volumes. When system resources are in contention, the PowerStore system devotes fewer compute resources to volumes with a low-performance policy.
Appliance balance for SAP HANA block storage workloads
PowerStore block storage resources are accessed using ALUA-optimized/non-optimized paths between the hosts and the two nodes within the PowerStore appliance. ALUA is an industry standard protocol for identifying optimized paths between a storage system and a host. The PowerStore system automatically chooses one of the nodes for the optimized path when the volume is mapped to the host. This node affinity feature maintains a balanced workload across the PowerStore nodes. You can view and modify node assignment using the PSTCLI command line. For the SAP HANA persistence (data and log) of a single SAP HANA server, it is a best practice to keep data and log assigned to alternate PowerStore nodes.
To view the current node assignment, run the following PSTCLI command:
pstcli -d <IP address> -u <username> -p <password> volume -name <volume name> show -output nvp | grep "ffin"
The following code snippet shows an example of the view node affinity command and its output:
pstcli -d 10.xxx.xx.xx -u admin -p *********** volume -name HANA-data-tdi-hana-storagetest01-vol show -output nvp | grep "ffin"
node_affinity = System_Selected_Node_A
node_affinity_l10n = System Selected Node A
To change the node affinity for a volume, run the following command:
pstcli -d <IP address> -u <username> -p <password> volume -name <volume name> set -node_affinity Preferred_Node_A (or Preferred_Node_B)
Appliance balance for SAP HANA file system workloads
For best performance, balance the file system workload across the PowerStore nodes. For the SAP HANA persistence (data and log), it is a best practice to always use two NAS servers, one on each PowerStore node. When creating the file systems, distribute them evenly across the two NAS servers.