Introduction to VMware vSAN

OVERVIEW

vSAN is a new VMware developed storage solution that is fully integrated with VMware’s Hypervisor or vSphere. vSAN abstracts and pools locally attached disks in a vSphere clustered Hosts and then creates a single logical disk, Once we provide the correct license, we can enable and provision vSAN in vSphere Web Client. Therefore vSphere now not only handles Compute resources but also the Storage resources and hence it is also called as Hyper-convergence and there is no need of any extra appliance installation for it to work. vSAN is also fully compitable with advanced vSAN features such as HA, DRS , FT etc

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WHY vSAN?

There are a number of issues with the existing traditional Storage technology :

1) Today’s NAS/SAN storage systems are not aligned with the virtual infrastructure, the virtual machines and applications do not really get complete support from the storage systems and hence there is a problem of performance.

2) NAS/SAN systems does not really understand the way virtual machines consume Storage, and how the applications running on virtual machines utilizes Storage

3) Even the Highend Storage can have performance issues due to the fact that all the data that is transmitted in and out of the Storage Box is over a medium or protocol.

4) Hence the data flow from Server is moved on a protocol (Ethernet, FC SAN, iSCSI) and after that it is processed by Storage controllers and finally at the Lun level hence multiple bottlenecks

vSAN Advantages :

  • vSAN is embeded in VMkernel and is activated with the licensing
  • No need to install any extra appliance
  • Overall CPU utilization is below 10%
  • Provides the shortest path for I/O
  • Removes application management overheads
  • Does not consume unncessary resources

vSAN Features

Policy Based Storage : vSAN provides policy based features. These policies can be applied during virtual machine provisioning using vCenter server

Scale up / Scale out : vSAN previously supported only Scale up , with version 6 we can also Scale out and more hosts to vSAN cluster

Server Side Storage Pool : In vSAN all the disks (flash/magnetic) that are populated in the physical server is called Server Side pool

External Storage Pool : in VSAN all the disks taht are provisioned using SAN/NAS Storage boxes are referred as external Storage pool

A replica copy of VM is stored on different Hosts and one of them acts as witness that has the details of Hosts

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Prerequisites

Hardware requirements:

  • SAS/ SATA/ PCIE Solid State Drive
  • SAS/ NLSAS/ SATA Hard disk Drive
  • 1Gb/ Recommended 10Gb Nic Cards
  • If there is a RAID card then it must support pass through mode
  • We can use SD cards or pendrives for installing ESXi (4 GB or 8 GB)

Software requirements:

  • vSphere 5.5U1 and above
  • Appropriate vCenter server

vSAN Installation procedure :
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  • Set up virtual SAN Network
  • Enable virtual SAN on Cluster in Web Client
  • Select Manual or Automatic for Diskgroup type
  • If you select Manual Create Diskgroup
  • Install vSAN Health Service

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