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Mapping volumes to an ESXi server
20 Dell EMC SC Series: Best Practices with VMware vSphere | 2060-M-BP-V
6 Mapping volumes to an ESXi server
Within the SC Series, mapping is the process of presenting a volume to a host. The following subsections
describe basic concepts on how vSphere treats different scenarios.
6.1 Basic volume mapping concepts
When sharing volumes between ESXi hosts for vMotion, HA, and DRS, for consistency it is recommended
that each volume is mapped to clustered ESXi hosts using the same LUN.
For example:
• There are three ESXi hosts named ESXi1, ESXi2, and ESXi3
• A new volume is created named "LUN10-vm-storage"
• This volume must be mapped to each of the ESXi hosts as the same LUN:
Volume: "LUN10-vm-storage" → Mapped to ESXi1 -as- LUN 10
Volume: "LUN10-vm-storage" → Mapped to ESXi2 -as- LUN 10
Volume: "LUN10-vm-storage" → Mapped to ESXi3 -as- LUN 10
6.2 Basic SC Series volume mappings
In SCOS versions 5.x and later, the mapping process is automated by creating a server cluster object. This
feature allows the volume to be mapped to multiple ESXi hosts simultaneously, automatically keeping the
LUN numbering consistent for all the paths.
Example of a server cluster object
As an added benefit, when a new ESXi host is placed into the server cluster, all the existing volume mappings
assigned to the cluster object are applied. Meaning that if the cluster has 100 volumes mapped to it,
presenting them to a new ESXi host is as simple as adding it to the cluster object.
Similarly, if the host is removed from the server cluster, the cluster mappings are removed. All I/O must be
stopped from the host before volumes are removed. Only volumes that are mapped to an individual host,
such as the boot volume, will remain once a host is removed from the server cluster.