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Performance counters are modeled using the PerfCounterInfo data object type. Each instance of a PerfCounterInfo data object contains metadata about a specific metric available from the system. The memory group (mem)of performance counters documented on this page are available from the PerformanceManager service interface. Memory Management and the VMkernelThe VMkernel maps guest physical memory to machine memory. However, because of the VMkernels unique memory-management techniques, such as ballooning, memory-sharing, swapping, and other techniques, guest physical memory-to-machine memory mapping does not have a 1:1 correspondence. Specifically, the VMkernel can:
Many of the VMkernels memory-management techniques require that VMware Tools be installed on the virtual machine. Be sure that the appropriate guest-OS-specific version of VMware Tools is installed on each virtual machine. Guest Physical Memory Compared to Machine MemoryEach counter definition in this table should be interpreted in the context of the entity to which it applies, as follows:
Memory SwappingThe VMkernel uses a "share before swap" optimization to reduce memory paging. Regardless of the page size in memory, the kernel uses a 4KB swap page size. The kernel will attempt to share 4KB pages; those pages that cannot be shared are swapped. For More InformationFor in-depth technical background about VMware memory management architecture, including information about ballooning, swapping, page sharing, idle memory tax, memory reclamation, touched pages, and so on, see the USENIX Association publication, Memory Resource Management in VMware ESX Server. See the Resource Management Guide for more information about configuring and managing resources, including memory. |
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| Counter | StatsType | Unit | Levels | RollupTypes | Labels | Entity | |||
|---|---|---|---|---|---|---|---|---|---|
| V | H | R | C | ||||||
| active | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) | Memory Active (Average) Memory Active (Minimum) Memory Active (Maximum) | • | • | • | • |
Amount of memory that is actively used, as estimated by VMkernel based on recently touched memory pages.
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| consumed | absolute | kiloBytes | 1 (4) | average (minimum) (maximum) | Memory Consumed (Average) Memory Consumed (Minimum) Memory Consumed (Maximum) | • | • | • | • |
Amount of memory consumed by a virtual machine, host, or cluster.
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| granted | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) | Memory Granted (Average) Memory Granted (Minimum) Memory Granted (Maximum) | • | • | • | • |
| Amount of machine memory or physical memory that is mapped for a virtual machine or a host. | |||||||||
| heap | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Heap (Average) Memory Heap Free (Minimum) Memory Heap Free (Maximum) Memory Heap (None) | ο | • | ο | ο |
| VMkernel virtual address space dedicated to VMkernel main heap and related data. For informational purposes only: not useful for performance monitoring. | |||||||||
| heapfree | absolute | kiloBytes | 2 (4) | average (none) | Memory Heap Free (Average) Memory Heap Free (None) | • | ο | ο | ο |
| Free address space in the VMkernels main heap. Varies based on number of physical devices and configuration options. There is no direct way for the user to increase or decrease this statistic. For informational purposes only: not useful for performance monitoring. | |||||||||
| mementitlement | absolute | number | 1 | latest | Worst Case Allocation | ο | • | ο | ο |
| Memory allocation as calculated by the VMkernel scheduler based on current estimated demand and reservation, limit, and shares policies set for all virtual machines and resource pools in the host or cluster. This counter is for internal use only and is not useful for performance monitoring. | |||||||||
| memUsed | absolute | kiloBytes | 3 | average | Memory Used | ο | • | ο | ο |
| Amount of used memory. Sum of the memory used by all powered on virtual machines and vSphere services on the host. | |||||||||
| overhead | absolute | kiloBytes | 1 (4) | average (minimum) (maximum) (none) | Memory Overhead (Average) Memory Overhead (Minimum) Memory Overhead (Maximum) Memory Overhead (None) | • | • | ο | ο |
Amount of machine memory allocated to a virtual machine beyond its reserved amount.
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| reservedCapacity | absolute | megaBytes | 2 | average | Memory Reserved Capacity | ο | • | ο | • |
| Total amount of memory reservation used by powered-on virtual machines and vSphere services on the host. Includes overhead amount. | |||||||||
| shared | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Shared (Average) Memory Shared (Minimum) Memory Shared (Maximum) Memory Shared (None) | • | • | ο | ο |
Amount of guest memory that is shared with other virtual machines,
relative to a single virtual machine or to all powered-on virtual machines on a host.
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| sharedcommon | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Shared Common (Average) Memory Shared Common (none) Memory Shared Common (Minimum) Memory Shared Common (Maximum) | • | • | ο | ο |
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Amount of machine memory that is shared by all powered-on virtual machines and vSphere services on the host. Subtract this metric from the shared metric to gauge how much machine memory is saved due to sharing:
shared - sharedcommon = machine memory (host memory) savings (KB) | |||||||||
| state | absolute | number | 2 | latest | Memory State | • | • | ο | ο |
One of four threshold levels representing the percentage of free memory on the host.
The counter value determines swapping and ballooning behavior for memory reclamation.
2 (hard) and 3 (low): Ballooning is favored over swapping. |
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| swapped | absolute | kiloBytes | 2 (4) | average | Memory Swapped (Average) Memory Swapped (Minimum) Memory Swapped (Maximum) Memory Swapped (None) | • | ο | ο | ο |
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Current amount of guest physical memory swapped out to the virtual machine's swap file by the VMkernel.
Swapped memory stays on disk until the virtual machine needs it. This statistic refers to VMkernel
swapping and not to guest OS swapping.
swapped = swapin + swapout |
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| swapin | absolute | kiloBytes | 1 (4) | average (minimum) (maximum) (none) | Memory Swap In (Average) Memory Swap In (Minimum) Memory Swap In (Maximum) Memory Swap In (None) | • | • | ο | ο |
Refers to VMkernel swapping. Amount swapped-in to memory from disk.
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| swapinRate | rate | kiloBytesPerSecond | 1 | average | Memory Swap In Rate | • | • | ο | ο |
| Rate at which memory is swapped from disk into active memory during the interval. This counter applies to virtual machines and is generally more useful than the swapin counter to determine if the virtual machine is running slow due to swapping, especially when looking at real-time statistics. | |||||||||
| swapout | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Swap Out (Average) Memory Swap Out (Minimum) Memory Swap Out (Maximum) Memory Swap Out (None) | • | • | ο | ο |
Amount of memory swapped-out to disk.
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| swapoutRate | rate | kiloBytesPerSecond | 1 (4) | average (minimum) (maximum) (none) | Memory Swap Out Rate | • | • | ο | ο |
| Rate at which memory is being swapped from active memory to disk during the current interval. This counter applies to virtual machines and is generally more useful than the swapout counter to determine if the virtual machine is running slow due to swapping, especially when looking at real-time statistics. | |||||||||
| swaptarget | absolute | kiloBytes | 2 | average (minimum) (maximum) (none) | Memory Swap Target (Average) Memory Swap Target (Minimum) Memory Swap Target (Maximum) Memory Swap Target (None) | • | ο | ο | ο |
| Target size for the virtual machine swap file. The VMkernel manages swapping by comparing swaptarget against swapped. Since swapped memory stays swapped until the virtual machine accesses it, swapped memory can be greater than the memory swap target, possibly for a prolonged period of time. This simply means that the swapped memory is not currently needed by the virtual machine and is not a cause for concern. | |||||||||
| swapunreserved | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Swap Unreserved (Average) Memory Swap Unreserved (Minimum) Memory Swap Unreserved (Maximum) Memory Swap Unreserved (None) | ο | • | ο | • |
| Amount of memory that is unreserved by swap | |||||||||
| swapused | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) | Memory Swap Used (Average) Memory Swap Used (Minimum) Memory Swap Used (Maximum) | ο | • | ο | • |
| Amount of memory that is used by swap. Sum of memory swapped of all powered on VMs and vSphere services on the host. | |||||||||
| sysUsage | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Used by vmkernel | ο | • | ο | ο |
| Amount of machine memory used by VMkernel for core functionality, such as device drivers and other internal uses. Does not include memory used by virtual machines or vSphere services. | |||||||||
| totalmb | absolute | megaBytes | 1 | average | Memory Total (Average) | ο | ο | ο | • |
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Total amount of machine memory of all hosts in the cluster that is
available for virtual machine memory (physical memory for use by the
Guest OS) and virtual machine overhead memory.
Memory Total = Aggregate host machine memory - (VMkernel memory + Service Console memory + other service memory) | |||||||||
| unreserved | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Unreserved (Average) Memory Unreserved (Minimum) Memory Unreserved (Maximum) Memory Unreserved (None) | ο | • | ο | ο |
| Amount of memory that is unreserved. Memory reservation not used by the Service Console, VMkernel, vSphere services and other powered on VMs user-specified memory reservations and overhead memory. This statistic is no longer relevant to virtual machine admission control, as reservations are now handled through resource pools. | |||||||||
| usage | absolute | percent | 1 (4) | average (minimum) (maximum) (none) | Memory Usage (Average) Memory Usage (Minimum) Memory Usage (Maximum) Memory Usage (None) | • | • | ο | ο |
| Memory usage as percentage of total configured or available memory. | |||||||||
| vmmemctl | absolute | kiloBytes | 1 (4) | average (minimum) (maximum) (none) | Memory Balloon (Average) Memory Balloon (Minimum) Memory Balloon (Maximum) Memory Balloon (None) | • | • | • | • |
Amount of memory allocated by the virtual machine memory control driver (vmmemctl), which is installed with VMware Tools. Its a VMware exclusive memory-management driver that controls ballooning.
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| vmmemctltarget | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Balloon Target (Average) Memory Balloon Target (Minimum) Memory Balloon Target (Maximum) Memory Balloon Target (None) | • | ο | ο | ο |
Target value set by VMkernal for the virtual machines memory balloon size. In conjunction with vmmemctl metric, this metric is used by VMkernel to inflate and deflate the balloon for a virtual machine, as follows:
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| zero | absolute | kiloBytes | 2 (4) | average (minimum) (maximum) (none) | Memory Zero (Average) Memory Zero (Minimum) Memory Zero (Maximum) Memory Zero (None) | • | • | ο | ο |
Memory that is contains 0s only. Included in shared amount. Through transparent page sharing, zero memory pages can be shared among virtual machines that run the same operating system.
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