Virtual Machine
CPU and Memory Sizing
This document is not a sizing instrument but delivers a guideline of technically possible configurations. For proper sizing, refer to BW on HANA (BWoH) and Suite on HANA (SoH) sizing documentation. The ratio between CPU and memory can be defined as 6.4 GB per vCPU for Westmere-EX, 8.53 GB per Ivy Bridge-EX and 10.66 GB per Haswell-EX vCPU. The numbers for Suite on HANA can be doubled.
See that the ESXi host and every virtual machine produce some memory overhead. For example, an ESXi server with 512 GB physical RAM can not host a virtual machine with 512 GB vRAM because the server would need some static memory space for its kernel and some dynamic memory space for each virtual machine. A virtual machine with eg. 500 GB vRAM would most likely fit into a 512 GB ESXi host.
This table shows the vCPU to vRAM ratio on a Haswell-EX server. Under "VMs per 3 TB Host", the maximal amount of VMs is shown considering two scenarios:
- BWoH prod
- This is the amount of virtual machines that can be deployed on one host for BW on HANA in a productive environment, that means, there is no resource overcommitment.
- CPU overcommit
- This is the amount of virtual machines that can be deployed on one host while allowing CPU overcommitment. Memory overcommitment is not recommended at all for HANA virtual machines.
vCPU | vRAM | VMs per 3 TB Host | ||
BWoH | SoH | BWoH prod | CPU overcommit | |
18 | 18 | 64 GB | 4** | 46 |
18 | 18 | 128 GB | 4** | 23 |
36 | 18 | 256 GB | 4 | 11 |
36 | 18 | 384 GB | 4 | 7 |
54 | 36 | 512 GB | 2 | 5 |
72* | 36 | 768 GB | 1 | 3 |
108* | 54 | 1 TB | 1 | 2 |
- | 72* | 1.5 TB | - | 1 |
- | 108* | 2 TB | - | 1 |
* 4 TB vRAM and 128 vCPU per VM with vSphere 6
** according to SAP Note 2024433, a physical CPU socket must not serve more than one VM
More details are available here:
SAP: SAP HANA Guidelines for running virtualized
VMware: Best Practices and Recommendations for Scale-Up Deployments of SAP HANA on VMware vSphere
VMware: Best Practices and Recommendations for Scale-Out Deployments of SAP HANA on VMware vSphere
Virtual Machine Creation
Create virtual machine with hardware version 10 (ESXi 5.5)
Select SLES 11 64-bit or RHEL 6 64-bit as Guest OS
Configure cores per socket
It is recommended to configure the cores per socket according to the actual hardware configuration, which means:
- 10 cores per socket on HANA certified Westmere-EX processors
- 15 cores per socket on HANA certified Ivy Bridge-EX processors
- 18 cores per socket on HANA certified Haswell-EX processors
Virtual SCSI controller configuration
Configure 4 virtual SCSI controllers of the type "VMware Paravirtual".
Configure virtual disks
To fully utilize the virtual resources, a disk distribution is recommended where the disks are connected to different virtual SCSI controllers. This improves parallel IO processing inside the guest OS.
The size of the disks can initially be chosen lower than the known requirements for HANA appliances. This is based on the capability of in increasing virtual disk size online.
Disk | Mount point | Size (old measure) | Size (new combined measure) |
root | / | 80 GB | 80 GB |
hanashared | /hana/shared | 1 * vRAM | 1 * vRAM |
hanadata | /hana/data | 3 * vRAM | 1 * vRAM |
hanalog | /hana/log | 1 * vRAM | vRAM < 512 GB: 0.5 * vRAM vRAM ≥ 512 GB: min. 512 GB |
Configure virtual network adapters
Configure one VMXNET3 adapter for each network and connect it to the corresponding port group. See that some networks are only configured on ESXi level, such as storage and backup network.
Enable Latency Sensitivity settings
To ensure the latency sensitivity, CPU and memory reservation has to be set, too. While the CPU reservation can vary, the memory reservation has to be set to 100 %. Check the box "Reserve all guest memory (All locked)".
After creating a VM, the guest OS installation can begin.
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