Dynamic Memory is a Hyper-V feature that was introduced with Windows Server 2008 R2 SP1 and is used to automatically reallocate memory between virtual machines that are running on a Hyper-V host. Dynamic Memory helps you to allocate virtual machine memory resources more efficiently while dramatically increasing virtual machine consolidation ratios. A number of improvements were made for Windows guests in Windows Server 2012, and - new in Windows Server 2012 R2 - Hyper-V now offers full dynamic memory support for Linux guests including:
- Minimum memory setting – being able to set a minimum value for the memory assigned to a virtual machine that is lower than the startup memory setting
- Hyper-V smart paging – which is paging that is used to enable a virtual machine to reboot while the Hyper-V host is under extreme memory pressure
- Memory ballooning – the technique used to reclaim unused memory from a virtual machine to be given to another virtual machine that has memory needs
- Runtime configuration – the ability to adjust the minimum memory setting and the maximum memory configuration setting on the fly while the virtual machine is running without requiring a reboot.
Also, up until now, if you wanted to take advantage of Linux Integration Services (LIS) for your Hyper-V environment, you had to go to the Microsoft download center, download the correct LIS package for your Linux distribution, and then manually install it on your Hyper-V servers. New for Windows Server 2012 R2 Hyper-V hosts, key Linux vendors are going to include LIS for Hyper-V in their standard distributions, so there is no manual step involved any longer in order for you to take advantage of the latest LIS capabilities.