Storage vMotion removes one large VM movement problem by allowing, conditions permitting, VM movement and/or replication to "foreign" (if licensed) hosts. High availability within a data center is increased, as is the ability to optimize host CPU cycles by match-fitting VM workloads with host spare-cycles. The Distributed Switch appliance and 10G Ethernet ports can make all the difference. Slower links make Storage vMotion less practical. It's our belief that VMware will sell, by accident, more 10G Ethernet switches.
Increasing high availability through the use of rapid failover to an alternate cabinet, room or even cross-country site is a direct function of communications bandwidth and managerial strength in terms of concurrent migration operations capability. For now, even if all the hypervisor hosts are licensed and running the latest version of VMware with fully configured Storage vMotion, there are upper-end practical limits to how much and how frequently VMs can be moved/migrated.
How We Tested
We tested vSphere 5.1 on an existing network consisting of two sides, lab and NOC. The lab is joined to the NOC at nFrame in Carmel Ind., by a Comcast Business Broadband link into a Gigabit Ethernet connection supplied by nFrame. At the NOC at nFrame are several HP, Dell, and Lenovo hosts connected by an Extreme Networks 10GBE X650 crossbar L2/L3 switch.
We installed freshly or upgraded various hosts with vSphere, as well as client machines, then installed the vCenter Server Appliance as described, and subsequently used this installed appliance as our access method to the converted vSphere5.1 hosts. We installed several trial VMs from scratch, and two (Windows 2008 R2 minimal configuration VMs) to be used in a trial of Storage vMotion between hosts, as described. We also noted features of the web client, and overall changes between supported features between vSphere 5.0 and 5.1.
Henderson is principal researcher for ExtremeLabs, of Bloomington, Ind. He can be reached at email@example.com.
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