High-availability clusters are groups of computers that support Oracle on VMware, SQL Server on VMware, and other virtual server applications. They can be accessed with a minimum of downtime in the event of a system failure.
A VMware High Availability (HA) error means that a failure has occurred for specific cluster. It usually means that one of the following types of problems has occurred:
- One or more VMware hosts have failed or become isolated from the network
- Reconnection of a previously isolated host
- Not enough resources in the cluster to satisfy the configured HA failover level
- The host capacity of the cluster is incapable of satisfying resource configuration constraints
If configured properly, VMware High Availability can reduce or eliminate Oracle on VMware, SQL Server on VMware, and other database downtime due to system failure:
- VMware High Availability responds by restarting virtual machines on other hosts with available capacity. An example of hardware failure is an isolation response, which generally occurs if a node of a VMware High Availability cluster is isolated from the network for 15 seconds or longer. VMware HA constantly monitors availability of physical servers in the cluster. VMware HA uses admission control to ensure that capacity is always available in order to restart all virtual machines affected by host failure.
- VMware High Availability also protects against operating system failure by continuously monitoring the performance metrics of a virtual machine and resetting if an operating system failure is detected.
In some cases, VMware HA may be unable to power on or reset an Oracle VMware, SQL Server VMware, or other virtual machines. When this happens, alarmVM will monitor and report these instances.
Confio IgniteVM helps identify the impact of VMware cluster high availability for sites running Oracle on VMware, SQL Server on VMware, and other databases. IgniteVM helps DBAs maintain performance and availability on virtual servers. IgniteVM is the only virtualization-aware database monitoring solution.
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