VSA Cluster中小企業無SAN環境解決方案

 VSA是爲中小企業無共享存儲的環境設計的，最多官方推薦3臺ESXi主機構成，減少部署成本，但是官方報價7999美金，不免是一種遺憾！！但是技術依然是有意義的，特別是在中國這個特殊的IT版權環境下

1.VSA整體構架

VSA Cluster with 2 ESXi Hosts

VSA Cluster with 3 ESXi Hosts

2.VSA網絡構架

Network Redundancy in a VSA Cluster with 2 Members

Network Redundancy in a VSA Cluster with 3 Members

3.VSA故障發生的時候的運行方式

Failover in a VSA Cluster with 2 Members

The following illustration depicts failover in a VSA cluster with 3 members.

Failover in a VSA Cluster with 3 Members

VSA羣集容量計算

The total capacity of a VSA cluster is the sum of the capacities of all VSA datastores. A VSA cluster can have 2 or 3 VSA datastores.

Note

The VSA datastore capacity is calculated after ESXi installation takes hard disk space for root, swap, and dumppartitions and after VSA installation reserves 20GB or more for local virtual machine swap files. Because of this, the following calculations are approximate.

In a VSA cluster with 4, 6, or 8 hard disks per ESXi host and a RAID10 configuration, the capacity of the VSA cluster depends on two variables.

■	Total hard disk capacity per ESXi host
■	Number of ESXi hosts in the VSA cluster (2 or 3)

The capacity of a VSA datastore equals the total hard disk capacity of the ESXi host divided by 4. This is due to the RAID10 configuration on each ESXi host and the mirroring of VSA volumes between VSA cluster members.

Determine the VSA datastore capacity by using the following formula.

VSA datastore capacity = hard disk capacity of an ESXi host / 4

Where

hard disk capacity of an ESXi host = the total capacity of the hard disks that are installed internally on the ESXi host

If you create a VSA cluster with hosts that have different total hard disk capacities, the lowest hard disk capacity from all ESXi hosts becomes the basis for calculating the capacity of every VSA datastore. In such a situation, some of the total hard disk capacity remains unused.

Example: Calculating the VSA Cluster Capacity in a Cluster with 3 ESXi Hosts with 8TB Hard Disk Capacity Per Host

Hard disk capacity per ESXi host = 8TB

Total hard disk capacity of all ESXi hosts = 24TB

VSA datastore capacity = 8TB / 4 = 2TB

Total VSA cluster capacity = 2TB * 3 hosts = 6TB

Example: Calculating the VSA Cluster Capacity in a Cluster with 3 ESXi Hosts with Different Capacities

Hard disk capacity of ESXi host 1 = 6TB

Hard disk capacity of ESXi host 2 = 8TB

Hard disk capacity of ESXi host 3 = 8TB

Total hard disk capacity = 22TB

VSA datastore capacity = 6TB / 4 = 1.5TB