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In terms of storage, VMware's EVO:RAIL appliances use a mix of magnetic and solid-state storage devices. Each of the four server nodes in an EVO:RAIL specify one single-level cell SATA disk on a module storage device as the ESXi boot device, a 400 GB multi-level cell enterprise-class solid-state disk (SSD) for read/write caching, and three 1.2 TB 10K RPM high-performance serial attached storage (SAS) disks for a total of 3.6 TB of working storage per node -- about 13 TB of usable storage capacity per appliance. The SSD and SAS disks are gathered up into a VMware Virtual SAN (VSAN) data store. Storage for VMs can be provisioned and managed from the pool of disk capacity.
When it comes to storage feature support, VMware's VSAN technology doesn't support storage compression or deduplication -- at least not yet -- so pooled EVO:RAIL storage cannot be deduplicated. Some organizations using virtual desktop instances can get around the lack of deduplication by adopting a linked clone approach to build a myriad of different desktop instances from a master image -- and simply applying small delta files to customize as necessary. Remember that storage can be replicated by implementing tools like VMware's vSphere Replication or protected with vCenter Site Recovery Manager.
The question of licensing gets a little trickier because the fate of your vSphere licenses depends on where you are in the EVO:RAIL ownership lifecycle. If you already have vSphere licenses and want to replace some of your current infrastructure with EVO:RAIL appliances, VMware's vSphere Loyalty Program allows customers to potentially utilize some vSphere licenses on the EVO:RAIL. However, terms, conditions and limitations do apply to the program, so it's important to discuss plans with your selected EVO:RAIL vendor -- such as Dell, HP or others -- before making a purchase commitment.
The licensing picture is a little bleaker if you already own an EVO:RAIL because licenses acquired with the EVO:RAIL are tied to the platform and cannot be transferred to another appliance. This means once the EVO:RAIL's three-year service period expires, you'll no longer be eligible for service or support until you buy another appliance.
The paradigm blurs the line between hardware, software and services. Everything is tied together, and some organizations may not be comfortable with this kind of arrangement.
Dig Deeper on Selecting storage and hardware for VMware environments
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