The other day when I was building a vSphere 6.0 environment up in my lab for testing I ran into an issue where performance was extremely slow in the web client and I was continually receiving an error that the VMware-dataservice-sca and vsphere-client status would change from green to yellow. When I deployed the VCSA/PSC appliance I choose “Tiny” as the size option. Even though my implementation is going to be under the 10 hosts and 100 VMs, I think this build was just not enough, and performance in the web client was just really lacking. Searching the VMware KB I came across 2144950. I found out this is a known issue affecting vCenter Server 6.0. Here are the steps that I used to work around the error and gain performance back in the web client.
First I added additional RAM to the appliance. Pretty straight forward, no magic there. Then I used SSH to connect to the appliance and ran the follow command:
cloudvm-ram-size -C XXX vsphere-client
Replace the XXX with the size in MB that you want to increase the heap size.
If you are running a Windows vCenter Server, find C:\ProgramFiles\VMware\vCenter Server\visl-integration\usr\sbin\cloudvm-ram-size.bat and run this command:
cloudvm-ram-size.bat -C XXX vspherewebclientsvc
Again swap out the XXX with the size in MB that you want to increase the heap size. Don’t forget to restart the vSphere client service.
DanCurr.com 
what is the size that has to be mentioned in xxx in case if tiny deployment.
In a Tiny installation the default configuration is 8GB of RAM. If you have not increased the RAM on the VCSA/PSC you can verify that if you run this command:
look for the TOTAL(MB). In vCenter Server 6.0 and higher, VMware introduced Dynamic Memory resizing. So if you just assign more memory to the VCSA/PSC and run that command again, you will see the vsphere-client service using more memory. However if you want to manually assign more memory to the service then you replace XXX with the amount in MB of memory that you want. The amount it up to you, assuming you don’t assign all the available RAM to that service.
I just upgrade from vCenter 5.5 to vCenter 6.0. Ever since the CPU and Memory have been running at or near 100%. I have noticed that the process that is taking up the memory/cpu is Java. I have only be able to find articles for this issue and vCenter 5.X My thought is that it has to do with the wrapper.conf file and wrapper.java.maxmemory setting. I have been unable to find any documentation on this for vCenter 6.0. FYI I am new to VM so please excuse my ignorance.
Hey Joe, sorry for the delay in this comment. Let me see if I can dig up some info for you on this. If you found your answer, please share it, as Im interested. Thanks!
I’ve found this article, and others with similar directions. However, at least on a Windows box, the service-layout file contains warnings that largeMB and MaxPermMB must equal 32000. This implies that if we want to bump MaxPermMB for the web client from 256 to 512, don’t we have to reduce the memory for other processes? If so, how would I determine from whom should I rob?