Host and Host Group Creation
This section describes the recommendations for creating provisioning objects (called hosts and host groups) on the FlashArray. The purpose is to outline the proper configuration for general understanding. It is important to note though, that the FlashArray vSphere Web Client Plugin will automate all of the following tasks for you and is therefore is a recommended mechanism for doing so.
The FlashArray has two object types for volume provisioning, hosts and host groups:
- Host—a host is a collection of initiators (iSCSI IQNs or Fibre Channel WWNs) that refers to a physical host. A FlashArray host object must have a one to one relationship with an ESXi host. Every active initiator for a given ESXi host should be added to the respective FlashArray host object. If an initiator is not yet zoned (for instance), and not intended to be, it can be omitted from the FlashArray host object. Furthermore, while the FlashArray supports multiple protocols for a single host (a mixture of FC and iSCSI), ESXi does not support presenting VMFS storage via more than one protocol. So creating a multi-protocol host object should be avoided on the FlashArray when in use with VMware ESXi.
In the example below, the ESXi host has two online Fibre Channel HBAs with WWNs of 20:00:00:25:B5:11:11:1C and 20:00:00:25:B5:44:44:1C.
- Host Group—a host group is a collection of host objects. Pure Storage recommends grouping your ESXi hosts into clusters within vCenter—as this provides a variety of benefits like High Availability and Dynamic Resource Scheduling. In order to provide simple provisioning, Pure Storage also recommends creating host groups that correspond to VMware clusters. Therefore, with every VMware cluster that will use FlashArray storage, a respective host group should be created. Every ESXi host that is in the cluster should have a corresponding host (as described above) that is added to a host group. The host group and its respective cluster should have the same number of hosts. It is recommended to not have more or less hosts in the host group as is in the cluster. While it is supported to have an unmatching count, it makes cluster-based provisioning simpler, and a variety of orchestration integrations require these to match. So it is highly recommended to do so.
BEST PRACTICE: Match FlashArray hosts groups with vCenter clusters.
Connecting Volumes to Hosts
A FlashArray volume can be connected to either host objects or host groups. If a volume is intended to be shared by the entire cluster, it is recommended to connect the volume to the host group, not the individual hosts. The makes provisioning easier, and helps ensure the entire ESXi cluster has access to the volume. Generally, volumes that are intended to host virtual machines, should be connected at the host group level.
Private volumes, like ESXi boot volumes, should not be connected to the host group as they do not (and should not) be shared. These volumes should be connected to the host object instead.
Pure Storage has no requirement on LUN IDs for VMware ESXi environments, and users should therefore rely on the automatic LUN ID selection built into Purity.