Reduced performance when administering ESX hosts in vCenter Server

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Normal management tasks take a long time to execute
• Reduced performance
• Tasks appear to stop responding when trying to start or stop a virtual machine
• Restarting the VMware Infrastructure/vSphere Client and vCenter Server does not help
• This issue affects only a specific ESX host in vCenter Server

poor-performance slow-performance

Environment

VMware ESX Server 3.0.x
VMware VirtualCenter 2.5.x
VMware ESX 4.0.x
VMware vCenter Server 4.0.x
VMware VirtualCenter 2.0.x

Resolution

This issue may occur if the Service Console of the ESX host has less memory.

 

Virtual machine management is performed using the hostd management agent on the ESX host. In some cases, you may experience these symptoms if resources, in particular Service Console memory become limited on the ESX host.

 

To resolve this issue, check for excessive system swapping. Any swapping slows down hostd and other management processes.

 

To check for excessive swapping:

1. Log in as root to the ESX host with an SSH client.
2. Run the command:
   
   # free
   
   The output appears similar to:
   
   total used free shared buffers cached
   Mem: 510708 487132 23576 0 68892 227908
   -/+ buffers/cache: 190332 320376
   Swap: 557016 0 557016
   
   This example output indicates that 512MB of memory is allocated to the Service Console and that 0MB of swap is being used. If your system indicates excessive swapping by showing a Swap used value which is almost the same as the Swap total and a low Swap free value, it is most likely suffering from resource starvation. For more information, see Checking for resource starvation of the ESX Service Console (1003496).

Additional Information

Checking for resource starvation of the ESX Service Console