# KSM and Auto-Ballooning in OpenNebula

**URL:** <https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786>\
**Category:** Product Support\
**Created:** [August 18, 2016, 4:10pm UTC](https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786 "2016-08-18T16:10:26Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![vynt-kenshiro](https://avatars.discourse-cdn.com/v4/letter/v/5fc32e/32.png) [@vynt-kenshiro](https://forum.opennebula.io/u/vynt-kenshiro)\
**Post date:** [August 18, 2016, 4:10pm UTC](https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786/1 "2016-08-18T16:10:26Z")

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Hello,

I am wondering, Dose OpenNebula support KSM and Auto-Ballooning? I use virsh command for show dominfo but the value of “Max memory” and “Used memory” are the same.

> root@hv002:~# virsh dominfo one-26  
> Id: 3  
> Name: one-26  
> UUID: ace938d1-8327-477e-9f7c-1c12d5d36d56  
> OS Type: hvm  
> State: running  
> CPU(s): 1  
> CPU time: 25.9s  
> Max memory: 262144 KiB  
> Used memory: 262144 KiB  
> Persistent: no  
> Autostart: disable  
> Managed save: no  
> Security model: apparmor  
> Security DOI: 0  
> Security label: libvirt-ace938d1-8327-477e-9f7c-1c12d5d36d56 (enforcing)

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**Author:** ![VURoland](https://yyz1.discourse-cdn.com/flex031/user_avatar/forum.opennebula.io/vuroland/32/7682_2.png) [@VURoland](https://forum.opennebula.io/u/VURoland)\
**Post date:** [August 18, 2016, 11:55pm UTC](https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786/2 "2016-08-18T23:55:05Z")

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Opennebula is just an orchestration tool, controlling KVM or VMware or Xen. What you probably want to know is how your hypervisor is setup by default. Looked into this because of this recent news: [https://www.vusec.net/projects/flip-feng-shui/](https://www.vusec.net/projects/flip-feng-shui/)  
In your case, here you can check what’s in use: [http://www.linux-kvm.org/page/KSM](http://www.linux-kvm.org/page/KSM)

and specifically:

Testing  
You can verify KSM is in action, by checking for the existence of some of its /sys files, under /sys/kernel/mm/ksm/  
They are:

pages\_shared

how many shared pages are being used

pages\_sharing

how many more sites are sharing them i.e. how much saved

pages\_unshared

how many pages unique but repeatedly checked for merging

pages\_volatile

how many pages changing too fast to be placed in a tree

full\_scans

how many times all mergeable areas have been scanned

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**Author:** ![vynt-kenshiro](https://avatars.discourse-cdn.com/v4/letter/v/5fc32e/32.png) [@vynt-kenshiro](https://forum.opennebula.io/u/vynt-kenshiro)\
**Post date:** [August 19, 2016, 1:25am UTC](https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786/3 "2016-08-19T01:25:06Z")

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Hi VURoland,

Thank you so much for your valuable information, especially Flip Feng Shui attack.

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**Author:** ![vladika\_mira](https://avatars.discourse-cdn.com/v4/letter/v/9de053/32.png) [@vladika\_mira](https://forum.opennebula.io/u/vladika_mira)\
**Post date:** [January 5, 2018, 12:52pm UTC](https://forum.opennebula.io/t/ksm-and-auto-ballooning-in-opennebula/2786/4 "2018-01-05T12:52:52Z")

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Hello, but what about memory ballooning? How it could be implemented for VMs?