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Table Of Contents
If the host has enough free memory, check the resource shares, reservation, and limit settings of the
virtual machines and resource pools on the host. Verify that the host settings are adequate and not lower
than those set for the virtual machines.
If the host has little free memory available, or if you notice a degradation in performance, consider taking
the following actions.
Table 162. Memory Performance Enhancement Advice
# Resolution
1 Verify that VMware Tools is installed on each virtual machine. The balloon driver is installed with VMware Tools and is critical
to performance.
2 Verify that the balloon driver is enabled. The VMkernel regularly reclaims unused virtual machine memory by ballooning and
swapping. Generally, it does not impact virtual machine performance.
3 Reduce the memory space on the virtual machine, and correct the cache size if it is too large. This frees up memory for other
virtual machines.
4 If the memory reservation of the virtual machine is set to a value much higher than its active memory, decrease the
reservation setting so that the VMkernel can reclaim the idle memory for other virtual machines on the host.
5 Migrate one or more virtual machines to a host in a DRS cluster.
6 Add physical memory to the host.
Memory (Balloon)
The Memory (Balloon) chart displays balloon memory on a host.
This chart is located in the Home view of the host Performance tab.
Table 163. Data Counters
Chart Label Description
Balloon Sum of the guest physical memory reclaimed by the balloon driver for all powered on virtual machines
on the host.
n
Counter: vmmemctl
n
Stats Type: Absolute
n
Unit: Megabytes (MB)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 1 (4)
Chart Analysis
To ensure best performance, the host memory must be large enough to accommodate the active memory
of the virtual machines. The active memory can be smaller than the virtual machine memory size. It
allows you to over-provision memory, but still ensures that the virtual machine active memory is smaller
than the host memory.
vSphere Monitoring and Performance
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