Oracle and SQL Databases

• CPU virtualization adds only a small amount of overhead. At the host level, enable hyper-threading

• Memory set reservations to avoid memory overcommitment. Size the memory suggested by DBA Administrator. Refer to the manufacturers’ recommendations for the number of vCPUs and memory within the VM.

• Network: Use the VMXNET3 paravirtualized NIC. VMXNET3 is optimized for virtual environments and designed to provide high performance

• Storage: Create dedicated datastores to service database workloads. Enable jumbo frames for IP-based storage using iSCSI and NFS, align VMFS properly, use Paravirtualized SCSI adapters for Oracle data files with demanding workloads. Applications requiring high levels of performance can be put onto dedicated datastores with dedicated logical unit numbers (LUNs) and can keep certain basic rules, such as not mixing types of I/O disks.

• For databases that generate random read type I/O, use RAID 5 or 5/0 for databases with a read/write ratio (R/W) of 70%R/30%W.

• Log files will follow a sequential write profile, use RAID 1 or 1/0 for logs. It is preferable to work with disks in Raw Device Mapping (RDM) mode, but VMDK disks can be also used.

Officially, Oracle databases are supported (by Oracle) in VMs only as of the 11G version (precisely 11.2.0.2). Any previous version is officially not supported.

SAP

Because SAP applications use a great deal of memory, VMware recommends not using memory overcommitment. To force this, a reservation must be made for the VM using the same value as the memory configured in the VM. The memory must be sized based on the memory actually used.

Some other considerations for SAP applications:

• The configuration of VMs in several vCPUs enables the use of the multithreading features of applications if they offer such support (which is usually the case). This leads to an increase in performance.

• Regarding storage, it is possible to mix RDM and vmdk disks in a SAP environment and to prefer one LUN mapping for each VM, to avoid I/O contentions.

• Using the vmxnet driver in VMs is recommended for improved performance. • The SAP Central Services component is a good choice for protection using the vSphere FT functionality in a VM with one vCPU.

Active Directory

The following best practices are recommended with AD:

• Do not pause AD VMs.

• Do not take snapshots of AD VMs because this can cause corruption and hinder performance.

• Use vSphere HA; because it has priority over all other VMs in the infrastructure, it has to be set to high priority.

• Configure the VM with one vCPU with a vmxnet3 virtual network card.

• Keep the PDC emulator as a physical server.