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Table Of Contents
If little free memory is available, or if you notice degradation in performance, consider taking the following
actions.
Table 1112. 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, this 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 (MBps)
The Memory (MBps) chart displays virtual machine memory swap rates.
This chart is located in the Home view of the Virtual Machine Performance tab.
Table 1113. Data Counters
Chart Label Description
swapinRate Average rate at which memory is swapped into the virtual machine.
n
Counter: swapinRate
n
Stats Type: Rate
n
Unit: MegaBytes per second (MBps)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 1 (4)
swapoutRate Average rate at which memory is swapped out of the virtual machine.
n
Counter: swapoutRate
n
Stats Type: Rate
n
Unit: MegaBytes per second (MBps)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 1 (4)
Chart Analysis
A virtual machine's memory size must be slightly larger than the average guest memory usage. This
enables the host to accommodate workload spikes without swapping memory among guests. Increasing
the virtual machine memory size results in more overhead memory usage.
If there is sufficient swap space, a high balloon value is not a performance issue. However, if the swapin
and swapout values for the host are large, the host is probably lacking the memory required to meet the
demand.
vSphere Monitoring and Performance
VMware, Inc. 89