Today, virtualization is under development by many companies and big companies trying to have their virtualization solution. Oracle VM is Oracle virtualization platform that it’s based on Xen hypervisor. You may know that any hypervisor has some limitations and configuration maximums and you should consider the limitation when you are deploying infrastructure or creating virtual machines. Oracle VM Manager Maximums em x86 Maximum SPARC Maximum Oracle VM Servers in a server pool (unclustered) 64 64 Oracle VM Servers in a server pool (clustered) 32 32 Number of servers 256 (16 servers * 16 server pools) 256 (16 servers * 16 server pools) Number of server pools 16 16 Number of configured virtual machines 5120 (20 virtual machines * 256 servers) 5120 (20 virtual machines * 256 servers) Number of running virtual machines 2,560 (10 virtual machines per server * 256 servers) 32768 (128 virtual machines per server * 256 servers) Fujitsu M10-4S, this limitation is 65536 (256 virtual machines per server * 256 servers) Oracle SPARC M-series servers, this limitation is 128 virtual machines per server * the number of physical domains (PDoms). Each physical domain acts as its own server with its own set of logical domains.
What’s OverCommitment? OverCommitment means virtual machines can use more resources than physical resources. CPU OverCommitment means you can create virtual machines with vCPU more than your server physical CPU, for example: Your server has two socket and each socket has 12 cores and also hyper-threading is enable, so you have 24 physical cores and 48 logical cores totally. But you can create and power on some virtual machines that those virtual machines have more than 48 cores totally. Memory OverCommitment means your virtual machines can use more memory than the physical machine (the host) has available. For example, you can have a host with 2GB memory and run four virtual machines with 1GB memory each. In that case, the memory is overcommitted. Advantages vs Disadvantages With OverCommitment, you can run more virtual machines but if you don’t have sensitive machine. If you have critical services on virtual machines, you need take care about OverCommitment because it can decrease your machines performance. How Take Care? You know, there is many native and third-party applications for monitoring vSphere environment but if you don’t have budget for buy monitoring software, you can use PowerCLI! There is a free PowerCLI module that you can...
Today, many companies have virtualized farms for their server infrastructure or desktop infrastructure and cloud services. The companies have critical information on their virtualized farms and keeping safe them is one of big concerns. Big companies or even small companies have security teams and the teams tries to keeping secure the environments in different layers. Most of the security products are working on physical layer or network and application layer but what about Hypervisor layer? vSphere Hardening VMware publishing a hardening guide for each vSphere version to help administrator to keep their environments more secure. vSphere hardening guides are available in the below link as Excel files: Download – Hardening Guides Previously, VMware had published an application to analyzing your vSphere environment and report you any security issue according to hardening guides. VMware Sphere Compliance Checker was available up to vSphere 5.5 and that’s not available for vSphere 6.x but you can use “VMware vRealize Configuration Manager” on this regard. Anyway, you can check and change security configurations accordion to hardening guides on your servers manually.
VMware has introduced new feature for kernel protection against memory error in ESXi. VMware called the new feature: Reliable Memory Technology or RTM. The feature is one of new features in ESXi 5.5! ESXi use a zone of memory that it’s more reliable than other offsets of memory, so risk of PSOD will be reduced. Also when part of memory has error, ESXi will stop to using the part of memory. There is some other technique against memory corruption or memory health error such as memory mirroring but Reliable Memory Technology can help you on this regard without loosing half of your memory capacity. Because memory mirroring is just like to RAID 1 on hard disks. Dell has introduced another feature on its server by using Reliable Memory Technology and called the new feature: Fault Resilient Memory or FRM. Fault Resilient Memory will provide “Fault Resilient Zone” and ESXi will put its kernel to the zone. The features can protect ESXi kernel and VMs as well. So if you have critical service on a VM, you can force ESXi to keep its memory on RTM or FRM zone to avoid memory error and down time for the machine. You can configure...
As you may know, you can install hypervisors on virtual machines for testing purpose. When you had installed ESXi on virtual machine, you did nesting virtualization. But think about installation process, any installation needs around 20 minutes and if you cloned a ESXi machine, it will be not worked properly on other virtual machine and you have to change your configuration manually. Now there is good solution and it’s ESXi virtual appliance. You can download ESXi OVA file and import it to your host or vCenter and also you can configure it during import process. ESXi virtual appliance is available at the below links: ESXi 6.0 Virtual Appliance download link ESXi 5.5 Virtual Appliance download link ESXi virtual appliance maybe updated after releasing new version. The last versions are: ESXi 6.0 U2 ESXi 5.5 U3 The ESXi virtual appliance including the below configurations: ESXi 6.0 U2: ESXi 6.0 Update 2 GuestType: ESXi 5.x (backwards compat) vHW 10 2 vCPU 6GB vMEM 2 x vmxnet3 vNIC 1 x 2GB HDD (ESXi Installation) 1 x 4GB SSD (for use w/VSAN, empty by default) 1 x 8GB SSD (for use w/VSAN, empty by default) VHV added dvFilter Mac Learn VMX params added disk.enableUUID VMX param added...
