Important VM Memory metrics
- Average memory active (highest) – the amount of memory that is estimated to be used based on memory touched.
- Memory granted (smallest) is a sum of all VMs running on an ESX server.
- Average memory Consumed (middle) – the amount of memory that the VMs actually pinned out of total configured capacity. Memory granted less memory saved by sharing.
- Average memory swapped in/out – virtual memory swapped to or from disk.
- Average memory swapped – total memory swapped out.
Memory counters to check in the VC
- Swap used
- Swap out
- Swap in
- Balloon – memory reclaimed.
How you know when host memory is the problem
- Consumed memory is approaching total host memory
- Active memory approaches total memory
- Ballooning is occurring
- Host swapping is occurring
Hoe you know when guest memory is the problem
- Guest VM memory has a high % utilization in vsphere client.
- Or View VM memory statistics inside the guest OS.
Ways to solve memory performance issues
- Determine where the memory utilization is coming from and find if it is valid.
- Reduce memory utilization if possible.
- Right-size VMs
- Reallocate resources in resource pool.
- Rebalance load with vmotion or DRS.
- Add more memory to the host or add another server to the cluster.