Some of you might be aware of the behaviour in vCenter Server 6.0 when the vmware-dataservice-sca and vsphere-client status change from green to yellow continually, and VMware KB # 2144950 provided as a workaround for this one.
However, two questions should be explained in the knowledge base above but seem to be missing.
The first question is current memory usage by the vsphere-client service. Knowing this data will help to choose the correct value for the vSphere Web Client’s maximum heap size when setting it manually. Fortunately, William Lam has a great article that explains a dynamic memory reconfiguration process when vCenter Server is booting up. One of the suggestions that William had was to use a CLI utility cloudvm-ram-size to monitor the memory usage.
cloudvm-ram-size -S | grep -e Service-* -e Linux* -e OS -e vsphere-client -e TOTAL
In the picture below, an output of the command shows memory usage in MB for the vCenter Server with external PSC in a small environment.
As a rule of thumb, to determine the maximum heap size for the vsphere-client service, I usually round the MaxMB value to the nearest gigabytes and add extra 512 MB as a reserve. In this example, AllocatedMB is 2,048 Mb + 512 MB = 2,560 MB.
Then, I set this parameter manually and restarted the vSphere Web Client service using the commands below.
cloudvm-ram-size -C 2560 vsphere-client | service vsphere-client restart
The dynamic memory algorithm adjusts the value of this setting automatically. After few minutes the service reinitialises, and memory allocation looks much better.
On rare occasions, you might notice that vAPI Endpoint service generate error messages after restarting vsphere-client. Restarting this service helps to resolve the problem.
service vmware-vapi-endpoint restart
Now we come to the second question: does this setting change survive the vCenter Server reboots? The answer is yes! And this is great news.
08/12/2016 – Update 1: You should reapply this setting after VCSA has been updated.
19/07/2017 – Update 2: VMware released a KB 2150757 to guide through the process of manually changing the heap memory on vCenter Server components in vCenter 6.x.