The shared storage design selects the storage technology for each type of cluster.

The storage devices for use by each type of cluster are as follows.

  • Management clusters use vSAN for primary storage and NFS for secondary storage.
  • Shared edge and compute clusters can use FC/FCoE, iSCSI, NFS, or vSAN storage. No specific guidance is given as user workloads and other factors determine storage type and SLA for user workloads.
Figure 1. Logical Storage Design
Management clusters use Virtual SAN for primary storage and NFS for secondary storage. Shared edge and compute clusters can use FC/FCoE, iSCSI, NFS, or vSAN storage.
Table 1. Design Decisions on Storage Type

Decision ID

Design Decision

Design Justification

Design Implication

SDDC-VI-Storage-001

When using a single availability zone in the management cluster, use vSAN and NFS shared storage:

  • Use vSAN as the primary shared storage platform.

  • Use NFS as the secondary shared storage platform for the management cluster.

By using vSAN as the primary shared storage solution, you can take advantage of more cost-effective local storage.

NFS is primarily for archiving and to maintain historical data. Using NFS provides large, low-cost volumes that you can flexibly expand regularly according to capacity needs.

The use of two different storage technologies increases the complexity and operational overhead.

You cannot configure multiple availability zones to use an NFS array in the event an availability zone fails.

SDDC-VI-Storage-002

In all clusters, ensure that at least 20% of free space is always available on all non-vSAN datastores.

If a datastore runs out of free space, applications and services in the SDDC, including but not limited to the NSX Edge core network services, the provisioning portal, and backup, fail.

Monitoring and capacity management must be proactive operations.