Virtualbox 5.0 - Linux Debian - Guest VM not freeing up used memory

[gxenakis]

Host: OS Type: Linux (3.16.0-4-amd64) VirtualBox: 5.0.16 (105871) Base Memory: 64441 MB Processor(s): Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz (8) HWVirtEx, PAE, Nested Paging, Long Mode (64-bit)

Guest VM: Debian 64bit Base Memory: 10240 MB Processor(s): 4 Boot Order: Optical, Hard Disk Acceleration: VT-x/AMD-V, Nested Paging, KVM Paravirtualization

After a proccess (eg. backup directories) uses memory when the process finishes the memory used doesn't free up but stays as used.

[Frank Mehnert]

This behavior was explained several times: The memory assigned to the guest is lazily allocated. That is, as long as the guest doesn't touch the RAM (from the guest's point of view this is 'physical' RAM, from the host's point of view this is virtual memory assigned to the guest) then this memory isn't allocated. Once the guest touches the RAM, it will be allocated on the host and not de-allocated until the VM process is terminated. This is normal VM behavior and nothing which can be changed easily as the VMM doesn't know what the guest is actually doing. The VMM provides a virtual hardware environment for the guest and the guest is free to use the provided resources.

[gxenakis]

Thanks for the info and sorry for not knowing that before.