Although vSAN shares many characteristics with traditional storage arrays, the overall behavior and function of vSAN is different. For example, vSAN can manage and work only with ESXi hosts and a single vSAN instance can support only one cluster.
vSAN and traditional storage also differ in the following key ways:
- vSAN does not require external networked storage for storing virtual machine files remotely, such as on a Fibre Channel (FC) or Storage Area Network (SAN).
- Using traditional storage, the storage administrator preallocates storage space on different storage systems. vSAN automatically turns the local physical storage resources of the ESXi hosts into a single pool of storage. These pools can be divided and assigned to virtual machines and applications according to their quality-of-service requirements.
- vSAN does not behave like traditional storage volumes based on LUNs or NFS shares. The iSCSI target service uses LUNs to enable an initiator on a remote host to transport block-level data to a storage device in the vSAN cluster.
- Some standard storage protocols, such as FCP, do not apply to vSAN.
- vSAN is highly integrated with vSphere. You do not need dedicated plug-ins or a storage console for vSAN, compared to traditional storage. You can deploy, manage, and monitor vSAN by using the vSphere Client.
- A dedicated storage administrator does not need to manage vSAN. Instead a vSphere administrator can manage a vSAN environment.
- With vSAN, VM storage policies are automatically assigned when you deploy new VMs. The storage policies can be changed dynamically as needed.