It’s like having a bank of PCs, configured for the different operating systems: Just boot up a test environment, install your software and run tests (all you need is lots of disk space to store all the different VMs).Ĭopy of a particular OS for each version of your software. You can create a number of test environments, each with a unique VM. If you’re writing cross-platform software, or you want to test an app on, say, Windows 7, Windows 10, Linux, and maybe on 32-bit as well as 64-bit (whatever you desire, in other words), this is where VMs are really handy. Build a Library of Different Operating Systems So why would you use a VM for development? Here are a few reasons I’ve found over the years. OS” is the OS installed in a particular VM. “Host PC” means the computer you are running Hyper-V (or its equivalent) on, “Guest Note the terms “Host PC” and “Guest OS.” While The VM typically uses a couple dozen GBs of disk Provide broadly similar capabilities: You can set up a VM and install Windows, All three (VirtualBox, Hyper-V and VMWare) There’s also VMware Workstation, which is meantįor commercial use and can run VMs. That can create virtual machines on X86-64, and is generally a bit faster at Virtualization technology on x86 and 圆4 CPUs.
It comes as part of Windows Pro you just need to enable it in Windows features,Īnd meanwhile you can’t run VirtualBox because Hyper-V uses VT-x, the Intel
Despite all the flak Oracle gets over itsĭatabases, MySQL, and Java, Virtual Box remains an excellent and free open-sourceĪfter a couple of years, I discovered the joys It wasĪll a bit “fiddly,” which is why I began exploring the potential of VMs.ĭiscovering VirtualBox was a godsend, and made
Installed a Linux distro on it but I quickly found out that the distro took upĪ lot of space, and I needed a KVM switch to manage two different PCs.
My development PC about six years ago I was keen to learn Linux, having been a Then you can investigate further to see whether it is the shared storage, network, physical CPU, or a physical RAM problem.I started using virtual machines (VMs) on One recommendation here is to isolate the problems and see whether it is the VM itself or the physical ESXi first. In this post, we gave you a few paths to explore, but we have just scratched the surface. Troubleshooting a performance problem is a job in and of itself. Check to make sure the firmware of your HBAs is up to date.Make sure that you have the latest BIOS on your physical hosts.Your host bus adapters (HBAs) are on VMware HCL and are certified for ESXi.If you identify a storming-related problem, you can also verify that: You can also reduce the number of VMs per LUN if you're not using VMware vSAN, which is not relevant for this situation. You can easily test it if you migrate your VMs to different, more performant storage, attached to the same host. Volumes created on top of spinning medias were slow, unreliable, and take a long time to rebuild if any of the underlying hard drives failed. Spinning media often caused poor performance in virtualization infrastructures. While the newest virtual infrastructure deployments get the best of the best, all-flash storage, an old infrastructure might still be using spinning storage. If you see only values of zero, as in our case, then your ESXi has still enough physical memory, and this memory reclaiming technique has not been used (yet).Ĭheck the MCTLSZ value for memory ballooning statistics Slow storage ^ Then look at the MCTLSZ value, which shows the amount of guest physical memory that was reclaimed (if any) by the balloon driver. On the main screen, type m for memory, then type f for fields and select the letter J (memory ballooning statistics). This is often the case when the physical memory of the host is fully utilized, and you have actually configured more memory for your VMs (overcommit).Īgain, we can use the esxtop command here and check the value. We can also check whether ESXi is struggling from a memory standpoint and reclaiming some memory from VMs. Finally, you can move some VMs to other hosts to free resources. If there is no limit configuration on the VM, then the load is too high and the only thing you can do is either increase the physical CPU number on the host (if possible) or reduce the number of virtual CPUs within each VM.
The CPU limit can be set on the per-VM level or at the resource pool level (if used). Make sure the VM is not configured with a CPU limit that is a limiting factor. This value should stay under 5% under normal workloads. This gives you an idea of how long (in percentage) the VM was ready but could not be scheduled to run on a physical CPU. If your ESXi has a CPU overload, you can connect via an SSH client such as Putty and initiate an esxtop command to verify the %READY field. Clear the Connect At Power On Checkbox Check CPU overload and CPU limit ^