Use this list of requirements and recommendations for reference related to shared storage, vSAN principal storage, and NFS supplemental storage in an environment with a single or multiple VMware Cloud Foundation instances. The design also considers whether an instance contains a single or multiple availability zones.

After you set up the physical storage infrastructure, the configuration tasks for most design decisions are automated in VMware Cloud Foundation. You must perform the configuration manually only for a limited number of design elements as noted in the design implication.

For full design details, see vSAN Design for VMware Cloud Foundation.

Table 1. vSAN Design Requirements for VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-REQD-CFG-001

Provide sufficient raw capacity to meet the initial needs of the workload domain cluster.

Ensures that sufficient resources are present to create the workload domain cluster.

None.

VCF-VSAN-REQD-CFG-002

Provide at least the required minimum number of hosts according to the cluster type.

Satisfies the requirements for storage availability.

None.
Table 2. vSAN ESA Design Requirements for VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-REQD-CFG-003

Verify the hardware components used in your vSAN deployment are on the vSAN Hardware Compatibility List.

Prevents hardware-related failures during workload deployment

Limits the number of compatible hardware configurations that can be used.
Table 3. vSAN Max Design Requirements for VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-MAX-REQD-CFG-001

Provide at least four nodes for the initial cluster.

A vSAN Max cluster must contain at least four hosts.

None.
Table 4. vSAN Design Requirements for a Multi-Rack Compute VI Workload Domain Cluster with VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-L3MR-REQD-CFG-001

Configure vSAN fault domains and place the nodes of each rack in their fault domain.

Allows workload VMs to tolerate a rack failure by distributing copies of the data and witness components on nodes in separate racks.

You must make the fault domain configuration manually vCenter Server after deployment and after cluster expansion.
Table 5. vSAN ESA Design Requirements for Multi-Rack Compute VI Workload Domain Cluster with VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-ESA-L3MR-REQD-CFG-001

Use a minimum of four racks for the cluster.

Provides support for reprotecting vSAN objects if a single-rack failure occurs.

Requires a minimum of four hosts in a cluster with adaptive RAID-5 erasure coding.

VCF-VSAN-ESA-L3MR-REQD-CFG-002

Deactivate vSAN ESA auto policy management

  • Not supported with vSAN fault domains.

  • Provides support for applying a compliant default storage policy on the vSAN datastore.

To align with the number of vSAN fault domains, you might have to create a default storage policy manually.
Table 6. vSAN OSA Design Requirements for a Multi-Rack Compute VI Workload Domain Cluster with VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-OSA-L3MR-REQD-CFG-001

Use a minimum of four racks for the cluster.

Provides support for reprotecting vSAN objects if a single-rack failure occurs.

  • Requires a minimum of four hosts in a cluster with RAID-1 configuration.
Table 7. vSAN Design Requirements for Stretched Clusters with VMware Cloud Foundation

Requirement ID

Design Requirement

Justification

Implication

VCF-VSAN-REQD-CFG-004

Add the following setting to the default vSAN storage policy:

Site disaster tolerance = Site mirroring - stretched cluster

Provides the necessary protection for virtual machines in each availability zone, with the ability to recover from an availability zone outage.

You might need additional policies if third-party virtual machines are to be hosted in these clusters because their performance or availability requirements might differ from what the default VMware vSAN policy supports.

VCF-VSAN-REQD-CFG-005

Configure two fault domains, one for each availability zone. Assign each host to their respective availability zone fault domain.

Fault domains are mapped to availability zones to provide logical host separation and ensure a copy of vSAN data is always available even when an availability zone goes offline.

You must provide additional raw storage when the site mirroring - stretched cluster option is selected, and fault domains are enabled.
VCF-VSAN-REQD-CFG-006 Configure an individual vSAN storage policy for each stretched cluster. The vSAN storage policy of a stretched cluster cannot be shared with other clusters. You must configure additional vSAN storage policies.

VCF-VSAN-WTN-REQD-CFG-001

Deploy a vSAN witness appliance in a location that is not local to the ESXi hosts in any of the availability zones.

Ensures availability of vSAN witness components in the event of a failure of one of the availability zones.

You must provide a third physically separate location that runs a vSphere environment. You might use a VMware Cloud Foundation instance in a separate physical location.

VCF-VSAN-WTN-REQD-CFG-002

Deploy a witness appliance that corresponds to the required cluster capacity.

Ensures the witness appliance is sized to support the projected workload storage consumption.

The vSphere environment at the witness location must satisfy the resource requirements of the witness appliance.

VCF-VSAN-WTN-REQD-CFG-003

Connect the first VMkernel adapter of the vSAN witness appliance to the management network in the witness site.

Enables connecting the witness appliance to the workload domain vCenter Server.

The management networks in both availability zones must be routed to the management network in the witness site.

VCF-VSAN-WTN-REQD-CFG-004

Allocate a statically assigned IP address and hostname to the management adapter of the vSAN witness appliance.

Simplifies maintenance and tracking, and implements a DNS configuration.

Requires precise IP address management.

VCF-VSAN-WTN-REQD-CFG-005

Configure forward and reverse DNS records for the vSAN witness appliance for the VMware Cloud Foundation instance.

Enables connecting the vSAN witness appliance to the workload domain vCenter Server by FQDN instead of IP address.

You must provide DNS records for the vSAN witness appliance.

VCF-VSAN-WTN-REQD-CFG-006

Configure time synchronization by using an internal NTP time for the vSAN witness appliance.

Prevents any failures in the stretched cluster configuration that are caused by time mismatch between the vSAN witness appliance and the ESXi hosts in both availability zones and workload domain vCenter Server.

  • An operational NTP service must be available in the environment.

  • All firewalls between the vSAN witness appliance and the NTP servers must allow NTP traffic on the required network ports.
Table 8. vSAN Design Recommendations for VMware Cloud Foundation

Recommendation ID

Design Recommendation

Justification

Implication

VCF-VSAN-RCMD-CFG-001

Provide sufficient raw capacity to meet the planned needs of the workload domain cluster.

Ensures that sufficient resources are present in the workload domain cluster, preventing the need to expand the vSAN datastore in the future.

None.

VCF-VSAN-RCMD-CFG-002

Ensure that at least 30% of free space is always available on the vSAN datastore.

This reserved capacity is set aside for host maintenance mode data evacuation, component rebuilds, rebalancing operations, and VM snapshots.

Increases the amount of available storage needed.

VCF-VSAN-RCMD-CFG-003

Use the default VMware vSAN storage policy.

  • Provides the level of redundancy that is needed in the workload domain cluster.

  • Provides the level of performance that is enough for the individual workloads.

You might need additional policies for third-party virtual machines hosted in these clusters because their performance or availability requirements might differ from what the default VMware vSAN policy supports.

VCF-VSAN-RCMD-CFG-004

Leave the default virtual machine swap file as a sparse object on vSAN.

Sparse virtual swap files consume capacity on vSAN only as they are accessed. As a result, you can reduce the consumption on the vSAN datastore if virtual machines do not experience memory over-commitment, which would require the use of the virtual swap file.

None.

VCF-VSAN-RCMD-CFG-005

Use the existing vSphere Distributed Switch instance for the workload domain cluster.

  • Reduces the complexity of the network design.

  • Reduces the number of physical NICs required.

All traffic types can be shared over common uplinks.

VCF-VSAN-RCMD-CFG-006

Configure jumbo frames on the VLAN for vSAN traffic.

  • Simplifies configuration because jumbo frames are also used to improve the performance of vSphere vMotion and NFS storage traffic.

  • Reduces the CPU overhead, resulting in high network usage.

Every device in the network must support jumbo frames.

VCF-VSAN-RCMD-CFG-007

Use a dedicated VLAN for vSAN traffic for each vSAN cluster.

  • Isolates the vSAN traffic only to the hosts in the cluster.

  • Reduces the amount of vSAN broadcast traffic that reaches a host to only the hosts in the cluster.

Increases the number of VLANs required.

VCF-VSAN-RCMD-CFG-008

Configure vSAN in an all-flash configuration in the default workload domain cluster.

Meets the performance needs of the default workload domain cluster.

All vSAN disks must be flash disks, which might cost more than magnetic disks.
Table 9. vSAN OSA Design Recommendations for with VMware Cloud Foundation

Recommendation ID

Design Recommendation

Justification

Implication

VCF-VSAN-RCMD-CFG-009

Ensure that the storage I/O controller has a minimum queue depth of 256 set.

Storage controllers with lower queue depths can cause performance and stability problems when running vSAN.

vSAN ReadyNode servers are configured with the correct queue depths for vSAN.

Limits the number of compatible I/O controllers that can be used for storage.

VCF-VSAN-RCMD-CFG-010

Do not use the storage I/O controllers that are running vSAN disk groups for another purpose.

Running non-vSAN disks, for example, VMFS, on a storage I/O controller that is running a vSAN disk group can impact vSAN performance.

If non-vSAN disks are required in ESXi hosts, you must have an additional storage I/O controller in the host.

VCF-VSAN-RCMD-CFG-011

Configure vSAN with a minimum of two disk groups per ESXi host.

Reduces the size of the fault domain and spreads the I/O load over more disks for better performance.

Using multiple disk groups requires more disks in each ESXi host.

VCF-VSAN-RCMD-CFG-012

For the cache tier in each disk group, use a flash-based drive that is at least 600 GB in size.

Provides enough cache for both hybrid or all-flash vSAN configurations to buffer I/O and ensure disk group performance.

Additional space in the cache tier does not increase performance.

Using larger flash disks can increase the initial host cost.
Table 10. vSAN ESA Design Recommendations for VMware Cloud Foundation

Recommendation ID

Design Recommendation

Justification

Implication

VCF-VSAN-RCMD-CFG-013

Activate auto-policy management.

Configures optimized storage policies based on the cluster type and the number of hosts in the cluster inventory. On changes to the number of hosts in the cluster or to host rebuild reserve, vSAN prompts you to make a suggested adjustment to the optimized storage policy.

None.

VCF-VSAN-RCMD-CFG-014

Activate vSAN ESA compression.

Improves performance.

PostgreSQL databases and other applications might use their own compression capabilities. In these cases, using a storage policy with the compression capability turned off will save CPU cycles.

You can disable vSAN ESA compressions for such workloads through the use of the Storage Policy Based Management (SPBM) framework.

VCF-VSAN-RCMD-CFG-015

Use NICs with a minimum 25-GbE capacity.

10-GbE NICs will limit the scale and performance of a vSAN ESA cluster because, usually, performance requirements increase over the lifespan of the cluster.

Requires 25-GbE or faster network fabric.
Table 11. vSAN Max Design Recommendations for VMware Cloud Foundation

Recommendation ID

Design Recommendation

Design Justification

Design Implication

VCF-VSAN-MAX-RCMD-001

Limit the size of the vSAN Max cluster to 24 hosts.

The total number of hosts for the vSAN Max cluster and vSAN compute clusters mounting the datastore must not exceed 128 hosts.

A vSAN Max cluster with 24 nodes provides support for up to 104 vSAN compute hosts which is a good compute-to-storage ratio.

Limits the maximum number of hosts.

VCF-VSAN-MAX-RCMD-002

If the vSAN Max cluster consists of only four hosts, do not enable the Host Rebuild Reserve.

If the auto-policy management feature is turned on, prevents vSAN Max from using adaptive RAID-5.

vSAN does not reserve any of this capacity and presents it as free capacity for vSAN to self-repair if a single host failure occurs.

VCF-VSAN-MAX-RCMD-003

Include TPM (Trusted Platform Module) in the hardware configuration of the hosts.

Ensures that the keys issued to the hosts in a vSAN Max cluster using Data-at-Rest Encryption are cryptographically stored on a TPM device.

Limits the choice of hardware configurations.
Table 12. vSAN Design Recommendations for Stretched Clusters with VMware Cloud Foundation

Recommendation ID

Design Recommendation

Justification

Implication

VCF-VSAN-WTN-RCMD-CFG-001

Configure the vSAN witness appliance to use the first VMkernel adapter, that is the management interface, for vSAN traffic.

Removes the requirement to have static routes on the witness appliance as vSAN traffic from the witness is routed over the management network.

The management networks in both availability zones must be routed to the management network in the witness site.

VCF-VSAN-WTN-RCMD-CFG-002

Place witness traffic on the management VMkernel adapter of all the ESXi hosts in the workload domain.

Separates the witness traffic from the vSAN data traffic. Witness traffic separation provides the following benefits:

  • Removes the requirement to have static routes from the vSAN networks in both availability zones to the witness site.

  • Removes the requirement to enable jumbo frames on the path between each availability zone and the witness site because witness traffic can use a regular MTU size of 1500 bytes.

The management networks in both availability zones must be routed to the management network in the witness site.