6.7

Table Of Contents
Solution
n
Verify that VMware Tools is installed on each virtual machine. The balloon driver is installed with
VMware Tools and is critical to performance.
n
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.
n
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.
n
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.
n
Migrate one or more virtual machines to a host in a DRS cluster.
n
Add physical memory to the host.
Solutions for Storage Performance Problems
Datastores represent storage locations for virtual machine files. A storage location can be a VMFS
volume, a directory on Network Attached Storage, or a local file system path. Datastores are platform-
independent and host-independent.
Problem
n
Snapshot files are consuming a lot of datastore space.
n
The datastore is at full capacity when the used space is equal to the capacity. Allocated space can be
larger than datastore capacity, for example, when you have snapshots and thin-provisioned disks.
Solution
n
Consider consolidating snapshots to the virtual disk when they are no longer needed. Consolidating
the snapshots deletes the redo log files and removes the snapshots from the vSphere Web Client
user interface.
n
You can provision more space to the datastore if possible, or you can add disks to the datastore or
use shared datastores.
Solutions for Disk Performance Problems
Use the disk charts to monitor average disk loads and to determine trends in disk usage. For example,
you might notice a performance degradation with applications that frequently read from and write to the
hard disk. If you see a spike in the number of disk read/write requests, check if any such applications
were running then.
Problem
n
The value for the kernelLatency data counter is greater than 4 ms.
vSphere Monitoring and Performance
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