Esxi Host Memory Slots
ESXi Host Memory The amount of memory required for compute clusters varies according to the workloads running in the cluster. When sizing memory for compute cluster hosts, consider the admission control setting (n+1), which reserves the resources of one host for failover or maintenance. Host free memory states ESXi maintains four host free memory states: high, soft, hard, and low, which are reflected by four thresholds. The threshold values are calculated based on host memory size. The figure below shows how the host free memory state is reported in ESXTOP. Show detailed controller information for controller in slot 0 ESXi 5.5 - /opt/hp. I have deleted everything on the datastore and removed it on the ESXi host. root@esxihost: smbiosDump grep -A 4 'Physical Memory Array' Physical Memory Array: #4096 Use: 0x03 (System memory) Location: 0x03 (Motherboard) Slots: 24 Max. To see the details of all physical memory installed on the server with the details of location, size etc. A recent feature in VMware ESXi allows you to use host SSD-caching as stopgap memory-management technique for memory-constrained servers. One of the more recent features that is available with ESXi.
During upgradation of a DELL PowerEdge R730/R830 server, we have increased the RAM from 24 GB to 88 GB and CPU from 1 to 2. After booting the system when we have checked from the BIOS we found the system is showing 2 CPU but showing RAM only 72 GB, 2 RAM of 8 GB was not installed correctly. At that time we were not able to identify the slots for which RAM was detected.
Later i googled that how to find system info, processor info, cache info, memory info, port connector details etc. and found the command smbiosDump through which we can get all the details related to system hardware through ESXi command line interface (CLI) after login as root.
How to check System and Hardware Information on a Linux Server
Esxi Check Memory Slots
HP-UX command to get Physical Memory Information
To log in to ESXi shell as a root, SSH service should be enabled and running on the ESXi host. To enable it you need to login to ESXi host through vSphere Client and go to Configuration >> Software >> Security Profile >> Properties select SSH click on options and start the SSH service.
After login to ESXi host through run the smbiosDump command to get the system information.
Below command show that maximum memory which can be installed on the server, maximum 2048 GB memory can be installed on this server
To see the details of all physical memory installed on the server with the details of location, size etc.
Processor info showing the details of the both processors
Cache Info showing the details of the L1, L2 and L3 cache for both the processors
Note: I have executed commands on ESXi host running on the ESXi 6.0.0
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vSphere 6 uses the well known memory reclamation techniques you may already know from previous versions:
- transparent page sharing (TPS)
- memory ballooning
- memory compression
- memory swapping
The memory reclamation technique that is used depends on the ESXi host memory state, which is determined by the amount of free memory of the ESXi host at a given time.
With vSphere 6 VMware introduced a new memory state, called “clear state“.
So vSphere 6 knows five different memory states associated with one or more memory reclamation techniques to reclaim memory:
But which treshold of free memory is associated with which memory state?
ESXi uses a value called “minFree” for the memory state calculation. minFree is a dynamic value and depends on the ESXi host memory configuration.
You can calculate minFree very easy for your ESXi host:
for the first 28 GB of physical RAM in the ESXi Host: minFree = 899 MB
+ add 1 percent of the remaining RAM to your calculation
Figure: „minFree calculation example vSphere 6:
In the example above the ESXi host has 100 GB memory:
for the first 28 GB RAM minFree = 899 MB, for the remaining 72 GB (100 GB – 28 GB) we have to add 1% to minFree: 1% of 720 GB = 720 MB -> minFree is 899 MB + 720 MB = 1619
Esxi Host Memory
Thresholds:
- high state: enough free memory available
- clear state: <100% of minFree
- soft state: <64% of minFree
- hard state: <32% of minFree
- low state: <16% of minFree
Esxi Host Memory Slots Game
If you want to know the memory state of one of your ESXi hosts you can use ESXTOP (extract from the vSphere 6 ESXTOP quick Overview for Troubleshooting” diagram):
Open ESXTOP and type “m” for the memory tab. The host memory state is displayed in the first line on the right.
You want to learn more about ESXTOP?
Esxi Host Memory Slots Download
Take a look at the vSphere 6 ESXTOP quick Overview for Troubleshooting” diagram: