Best Practices for VMFS Configuration

The following best practices are recommended:

• Generally, you should create VMFS volumes between 600 GB and 1 TB and use 15 to 20 active vmdks per volume (no more than 32). (A VM can have several active vmdks.)

• For environments that require high levels of performance, such as Oracle, Microsoft SQL, and SAP, the RDM mode is preferable.

• VMware recommends the use of VMFS over NFS because VMFS offers the complete set of capabilities and allows the use of RDM volumes for I/O-intensive applications.

• To avoid significant contentions, avoid connecting more than eight ESXi servers to a LUN ( so no more than eight ESXi hosts per Cluster).

• Avoid placing several VMs with snapshots on the same VMFS.

• Avoid defining the DRS as aggressive because this will trigger frequent VM migration from one host server to another and, therefore, frequent SCSI reservations.

• Separate production LUNs from test LUNs, and store ISO files, templates, and backups on dedicated LUNs.

• Align vmdk partitions after the OS is configured for new disks.

• Avoid grouping several LUNs to form a VMFS because the different environments cannot be separated (the production environment, test environment, and templates), which increases the risk of contentions, with more frequent reservations.

• Avoid creating one VMFS per VM because it increases the number of LUNs and makes management more complex while limiting expansions to 256 LUNs or 256 VMs.