6.0.1

If little free memory is available, or if you notice degradation in performance, consider taking the following
actions.
Table 1‑109. 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 1‑110. 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.
If a virtual machine has high ballooning or swapping, check the amount of free physical memory on the
host. The host might require more memory resources. If it does not, check the resource shares, reservation,
and limit 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 machine.
If memory usage is high or you notice degredation in performance, consider taking the following actions.
vSphere Monitoring and Performance
78 VMware, Inc.