Memory (MB)

The Memory (MB) chart displays consumed memory for the cluster.

This chart is located in the Home view of the Cluster Performance tab.

Table 13. Data Counters

Chart Label	Description
Consumed	Amount of host machine memory used by all powered on virtual machines in the cluster. A cluster's consumed memory consists of virtual machine consumed memory and overhead memory. It does not include host-specific overhead memory, such as memory used by the service console or VMkernel. ■ Counter: consumed ■ Stats Type: Absolute ■ Unit: MegaBytes (MB) ■ Rollup Type: Average (Minimum/Maximum) ■ Collection Level: 1 (4)
Total	Total amount of machine memory of all hosts in the cluster that is available for virtual machine memory (physical memory for use by the Guest OS) and virtual machine overhead memory. Memory Total = Aggregate host machine memory - (VMkernel memory + Service Console memory + other service memory) Note The totalmb data counter is the same as the effectivemem data counter, which is supported only for backward compatibility.   ■ Counter: totalmb ■ Stats Type: Absolute ■ Unit: MegaBytes (MB) ■ Rollup Type: Average (Minimum/Maximum) ■ Collection Level: 1 (4)

Chart Analysis

Memory usage is not an indicator of performance problems. Memory can be high if a host is swapping or ballooning, which can result in virtual machine guest swapping. In such cases, check for other problems, such as CPU over-commitment or storage latencies.

If you have constantly hig memory usage in a cluster, resource pool, or vApp, consider taking the actions listed in Table 14.

Table 14. Memory Performance Enhancement Advice

#	Resolution
1	Verify that VMware Tools is installed on each virtual machine.
2	Verify that the balloon driver is enabled. The balloon driver is installed with VMware Tools and is critical to performance. The VMkernel regularly reclaims unused virtual machine memory by ballooning and swapping. Generally, this does not impact virtual machine performance.
3	If the balloon value is high, check the resource shares, reservation, and limit of the virtual machines and resource pools on the hosts. Verify that the host's settings are adequate and not lower than those set for the virtual machine. If there is free memory on the hosts and the virtual machines are experiencing high swap or balloon memory, the virtual machine (or resource pool, if it belongs to one) has reached its resource limit. Check the maximum resource limit set on that host.
4	If the cluster is not a DRS cluster, enable DRS. In Inventory > Cluster > Edit Settings, select Enable VMware DRS.
5	If the cluster is a DRS cluster: ■ Increase the number of hosts, and migrate one or more virtual machines onto the new host. ■ Check the aggressiveness threshold. If the value is low, increase the threshold. This might help avoid hot spots in the cluster.
6	Add more physical memory to one or more hosts.