vSAN is a policy-driven software-defined storage solution that is integrated with vSphere. vSAN simplifies storage provisioning and management in the software-defined enterprise.
vSAN is an enterprise storage solution with full vSphere integration. vSAN includes a distributed layer of software within the ESXi hypervisor and can perform the following functions:
Aggregate local storage together into a single cluster-wide shared datastore
Utilize networking for host communications
Enhance server hardware resource utilization
Reduce data center requirements for power and cooling
Storage Device Support:
Operational Benefits:
Maximizes use of existing server infrastructure.
Eliminates need for separate SAN hardware.
Results in lower total cost of ownership (TCO).
Licensing:
Activating vSAN provides a 60-day trial license with full feature access.
Networking Importance:
vSAN provides four types of deployment architectures to meet enterprise needs.
vSAN Cluster Types
Single Site vSAN Cluster: One site 3 to 64 hosts
Two-Node Cluster: 2 hosts at remote site, 1 witness at alternative site
vSAN Stretched Cluster: Up to 20 hosts at each Site; 1 Witness at a Third Site
Cross-Cluster Capacity Sharing: vSAN Clusters Accessing Other vSAN Clusters
vSAN Datastore:
Single cluster-wide datastore
Easily scalable by adding more storage devices/hosts
Managed through vCenter
Storage policies determine the data storage method
Appears like any other supported datastore
vSAN Data Storage
vSAN is an object-based storage solution when compared to block-based storage solutions such as VMFS or file-based storage solutions like NFS.
Available vSAN Storage Architectures
vSAN 8 supports two types of storage architectures
Original Storage Architecture (OSA) – diskgroups configuration
max. of 5 diskgroups per node
1 cache device in each diskgroup
up to 7 capacity devices (ssd or HDD)
vSAN All-Flash dg requires at least 10Gbps network bandwidth
Reads from capacity tier and cache is a100% allocated for writes
Hybrid Disk Group:
SSD used for caching and HDD for capacity
cache tier: 70% for reads and 30% for writes
capacity tier:
read hit – read from cache
hit missed – copy from capacity tier to cache tier and then return
Express Storage Architecture (ESA). – (introduce in vsphere 8.0.x)
single-tier called storage pool
uses NVMe-based flash devices.
no cache but performance component is enabled
vSAN storage Policies
define how data is placed on disk
A single policy can be applied to a group of VMs, a single VM, or a single VMDK