I have an ESXi host with 4GB ram running 1 virtual machine which has 2GB allocated. For some reason I only have 65MB remaining? Is this normal behaviour? I can't add the host to vSphere Center and I think it's because it doesn't have the RAM to install the tools. The error is 'Cannot install the vCenter agent service. Unknown installer error'.
This is how my memory looks.
Host Resources
Capacity: 4083.56MB
Usage: 2897.00MB
Resource Allocation
Total Capacity: 2279MB
Reserved Capacity: 2214MB
Overhead Reservation: 0MB
Available Capacity: 65MB
Configuration
Total: 4083.6MB
System: 558.6MB
Virtual Machines: 3525MB
Why under resource allocation is the capacity only 2279MB? Is my one virtual machine allocating all the available RAM to itself?
It looks to me that the VM, or a resource pool, has a RAM reservation set on it.
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That sounds about right to me! So on my VMs properties my resource allocationreads as follows:
Shares: Normal
Reservation: 2048MB
Limit: Unlimited
Should I set the limit at 2048MB? The most I can allocate under limit is only 2278MB anyway so where has the other 1GB RAM gone?
Stop the VM, then change the reservation to zero.
HTH
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I see. So the reservation is over and above what the VM is already using?
1.Stop the Vm and set the reservation to zero.
2.The remaining 1GB RAM is basiaclly used by the service console of the ESX server.
On ESX the "memory total capacity" on the resource allocation sheet is always about 1200MB less than the "Memory virtual machines" figure on the configuration, memory tab.
Basically, consider the footprint of ESX to be about 2GB. Since in the VM properties another 2GB has been reserved exclusively for that VM, there is nothing left. If you have vmware tools installed in the guest and no reservation, ESX can "get back" RAM from the guest through the guest's own paging mechanisms (or vSwapping, which is much harsher).
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Thanks for your help! What threw me is that it said SYSTEM is using 558MB. Basically ESXi uses much more RAM than it says it is I guess... I'll stop the VM when I get a chance and reduce the reservation.