Product Documentation

Managing load balancing across servers

Feb 24, 2016

A vDisk can be configured so that a single server provides that vDisk, or configured so that multiple servers can provide the vDisk using a load balancing algorithm.

To configure load balancing on a vDisk
  1. Right-click on the vDisk in the Console, then select the Load Balancing... menu option.
  2. Select to enable load balancing or to assign a single Provisioning Server to provide this vDisk, then click OK. Refer to the table below for dialog details.
Note: For details on configuring for high availability, refer to Managing for Highly Available Implementations.
The following table describes the vDisk Load Balancing dialog.
Field/Button Description
Use the load balancing algorithm

Provides the option to enable or disable the load balancing algorithm, which selects the server that is least busy to provide this vDisk to target devices.

Subnet Affinity. When assigning the server and NIC combination to use to provide this vDisk to target devices, select from the following subnet settings:
  • None – ignore subnets; uses least busy server. None is the default setting.
  • Best Effort – use the least busy server/NIC combination from within the same subnet. If no server/NIC combination is available within the subnet, select the least busy server from outside the subnet. If more than one server is available within the selected subnet, perform load balancing between those servers.
  • Fixed – use the least busy server/NIC combination from within the same subnet. Perform load balancing between servers within that subnet. If no server/NIC combination exists in the same subnet, do not boot target devices assigned to this vDisk.
Rebalance Enabled. Enable to rebalance the number of target devices on each server in the event that the trigger percent is exceeded. When enabled, Provisioning Services checks the trigger percent on each server every ten minutes.
Note: Rebalancing will not occur if there are less than five target devices on each server, or if more than 20% of the target devices are currently booting. A target device that is currently booting will not be moved to a different server.

Trigger Percent The percent of overload that is required to trigger the rebalancing of target devices. For example: If the trigger percent is equal to 25%, rebalancing occurs if this server has 25% more load in comparison to other servers that can provide this vDisk. Values between 5 - 5000; default is 25.

Use this server to provide the vDisk To assign a specific server to provide this vDisk, enable the Use this server to provide the vDisk radio button.