Shulou(Shulou.com)06/03 Report--

Design and optimize vSAN fault domain

The vSAN fault domain feature instructs vSAN to distribute redundant components across servers in each computer rack. As a result, you can protect your environment from rack-level failures, such as power outages or disconnections.

Fault domain construction

VSAN requires at least three failure domains to support PFTT = 1. Each failure domain contains one or more hosts. The fault domain definition must identify physical hardware constructs that may represent potential failure areas, such as a single computer cabinet.

If possible, use at least four failure domains. When using three failure domains, some data withdrawal modes are not supported, and vSAN cannot reprotect data after a failure. In this case, you need to rebuild other failure domains with capacity that cannot be used if only three failure domains are used.

If the failure domain is enabled, vSAN applies the active virtual machine storage policy to the failure domain (not to a single host).

The number of failure domains in the cluster is calculated based on the allowed number of failures Primary level (PFTT) attribute in the storage policy that is scheduled to be assigned to the virtual machine.

Number of fault domains = 2 * PFTT + 1

If the host is not a member of the failure domain, vSAN interprets it as a separate failure domain.

Use the failure domain to deal with multiple host failures

Consider a cluster of four server racks, each containing two hosts. If you set the allowable primary level of failures to 1 and do not enable the failure domain, vSAN may store two copies of the object in the same cabinet as the host. Therefore, the application may have a potential risk of data loss in the event of a rack-level failure. When configuring hosts that may fail at the same time to a separate failure domain, vSAN ensures that each protection component (copy and witness) is placed in a separate failure domain.

If you want to add hosts and capacity, you can configure or define a failure domain using an existing failure domain.

When using a failure domain for storage load balancing and fault tolerance, consider the following guidelines:

1. There are enough failure domains to meet the primary level of the allowable number of failures configured in the storage policy. Define at least three failure domains. For best protection, define at least four domains.

two。 Assign the same number of hosts to each failure domain.

3. Use a host with a unified configuration.

4. If possible, dedicate a failure domain with available capacity to rebuild the data after a failure.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.