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Special requirements apply to configuring the persistence (data and log) of an SAP HANA VM. Create the persistence of production SAP HANA VMs by adding disks for data and log from the vSAN storage pool to the VMs.
A VMware best practice is to use a dedicated SCSI controller for the SAP HANA persistence. Configure the SCSI controller as VMware Paravirtual. The example that is shown in the following figure uses SCSI Controller 0 for the system device, SCSI Controller 1 for the LVM data devices, and SCSI Controller 2 for the LVM log devices:
Use the SAP Quick Sizer tool to determine the required capacity for the SAP HANA data and log devices. If the sizing details are not available, Dell Technologies recommends configuring the sizes of the data and log devices based on the memory size of the SAP HANA VM. For data, configure 2 x RAM. For log, configure 0.5 to 1 x RAM (up to a maximum of 512 GB).
Add the capacity of the data and the log device to get the total required capacity for the SAP HANA persistence of the VM.
Define a storage policy for the SAP HANA physical devices that are deployed on the vSAN datastore. While the default vSAN storage policy is adequate for the system device, a dedicated storage policy is required for the SAP HANA persistence devices to meet the SAP performance requirements. The following figures show the rules that the Dell SAP engineering team defined in the storage policy:
The vSAN storage policy requirements for the SAP HANA persistence are:
Linux LVM distributes the logical volumes that the application uses across multiple physical devices—in this case, vSAN devices. Distribute the persistence for the data device across eight physical devices and the persistence for the log device across four physical devices.
In the following example, the Dell SAP team needed 500 GB capacity for the SAP HANA data device and 200 GB for the SAP HANA log device—a total of 700 GB for the persistence. The team therefore created eight 62 GB vSAN devices for data and four 52 GB devices for log.
Every volume uses the VM storage policy SAP_HANA and is assigned to the dedicated SCSI controller, as shown in the following figure:
After the SAP HANA VM starts, you must format and mount the persistence before you install the SAP HANA software.
To format the data and log devices:
mkfs.xfs /dev/sdb ; mkfs.xfs /dev/sdc
mkdir -p /hana/data /hana/log
mount /dev/sdb /hana/data ; mount /dev/sdc /hana/log