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ME4 Series array settings
15 Dell EMC PowerVault ME4 Series and VMware vSphere | 3922-BP-VM
5 ME4 Series array settings
This section includes ME4 Series array settings that ensure a smooth and consistent data-center
environment.
5.1 Missing LUN Response
The setting for Missing LUN Response can be found in ME Storage Manager under Action > Advanced
Settings > Cache.
The default setting of Illegal Request is compatible with a VMware vSphere environment and should not be
changed. Some operating systems do not look beyond LUN 0 if they do not find a LUN 0, or cannot work with
noncontiguous LUNs. This parameter addresses these situations by enabling the host drivers to continue
probing for LUNs until they reach the LUN to which they have access. This parameter controls the SCSI
sense data returned for volumes that are not accessible because they do not exist or have been hidden
through volume mapping.
In a vSphere environment, ESXi interprets the Not Ready reply as a temporary condition. If a LUN is
removed from an ESXi host without properly un-mounting the datastore first, and if the missing LUN response
is set to Not Ready, ESXi may continue to query for this LUN indefinitely.
Missing LUN Response setting
5.2 Host groups
For ease of management with ME4 Series arrays, initiators that represent a server can be grouped into an
object called a host, and multiple host objects can be organized into an object called a host group. Doing so
enables mapping operations for all initiators and hosts in a group to be performed in one step, rather than
mapping each initiator or host individually. A maximum of 32 host groups can exist.