Reference Guide

vStart 100 and 200 VMware vSphere Reference Architecture
Dell Inc 20
6 Scalability
When adding additional servers or storage to the rack, power, weight, and cooling requirements must
be taken into account. The power limits of PDUs and UPS must be understood prior to installing a new
system.
Switch ports on both the LAN and SAN switches are available for expansion. Those ports must be
enabled and configured to support the new servers and/or storage arrays.
Adding new servers to the ESXi Cluster: If additional VMs will be deployed that will exceed current
resource capabilities, or the ESXi cluster has reached its acceptable maximum (CPU and memory)
resource utilization, then additional servers can be added to the cluster.
Previously created iSCSI volumes on the EqualLogic array may require modifications to the access
controls to grant access to the newly added servers.
When adding servers to an ESXi cluster, it is recommended that the configuration be identical to the
other systems in the cluster. If this is not achievable, then there may be restrictions on certain actions
such as vMotion between the differing systems. To understand vMotion compatibility requirements,
refer to the Dell whitepaper, VMware vMotion and 64-Bit Virtual Machine Support for Dell PowerEdge
Systems Compatibility Matrix, available at
http://support.dell.com/support/edocs/software/eslvmwre/VS/index.htm.
For quick addition of a new server and for the ESXi cluster to be uniform, host profiles can be used. A
host profile is created from an existing server on the same ESXi cluster. It will capture the networking,
storage and security settings from the validated configuration. A new server with the basic vSphere
installation can be added to the cluster and the host profile can then be applied to setup the
networking, storage, and security configuration. Note that host profiles require vSphere Enterprise Plus
license edition.
Adding new storage to the EqualLogic group: New EqualLogic arrays can be added to the existing
EqualLogic group. As each new array is added to the storage group, the storage capacity and
performance, in terms of both bandwidth and IOPS, are increased. This increased capacity can be
utilized without downtime. When a new array is added to an existing pool, the existing data will
automatically be distributed to the newly added array.
If EqualLogic thin provisioning was utilized and virtual capacity allocated is nearing the limit of physical
capacity, then adding an additional storage array to the constrained pool will address this issue.