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SolusVM: Cannot Allocate Memory Error – How to fix?

by | Jun 8, 2021

Stuck with SolusVM: Cannot Allocate Memory Error? We can help you.

Recently, one of our customers came across a “cannot allocate memory” error. This can happen while we boot KVM VPS in SolusVM.

As part of our Server Management Services, we assist our customers with several SolusVM queries.

Today, let us discuss how we can resolve this error easily.


What is SolusVM: Cannot Allocate Memory Error?

It is quite common that users experience that they are unable to boot KVM VPS in SolusVM.

In such situations, we often notice that the KVM VPS does not start in SolusVM – VPS stays offline.

In addition, we come across either of the below errors, if we press the Reboot (Debug) button on the page, SolusVM > Virtual Servers > the affected VPS.

qemu-kvm: cannot set up guest memory ‘pc.ram’: Cannot allocate memory


Domain kvm101 has been undefined
Domain kvm101 defined from /home/kvm/kvm101/kvm101.xml
Domain kvm101 marked as autostarted
error: Failed to create domain from /home/kvm/kvm101/kvm101.xml
error: internal error: qemu unexpectedly closed the monitor: ioctl(KVM_CREATE_VM) failed: 12 Cannot allocate memory
2021-03-23T08:56:18.128294Z qemu-kvm: failed to initialize KVM: Cannot allocate memory

These errors mean we do not have enough memory on the node. This can be due to cache.

Often, it is quite possible that there is a lot of cached memory on the KVM Slave.


How to solve this error?

Moving ahead, let us see a method our Support Techs employ to fix this error.

The best solution here is to clear up the cached memory.

To do so,

  1. Firstly, we connect to the node via SSH
  2. Then we free up the cached memory:
    # sync; echo 3 > /proc/sys/vm/drop_caches

Finally, suppose the solution does not help. Then we add RAM to the node.

[Need help with the fix? We are here for you]



To conclude, this error occurs while booting KVM VPS in SolusVM. Today, we saw how our Support Techs fix this error for our customers.


Never again lose customers to poor server speed! Let us help you.

Our server experts will monitor & maintain your server 24/7 so that it remains lightning fast and secure.


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1 Comment

  1. WHP

    Very helpful, thanks! You also don’t need to reboot. Solus will auto boot once the cache is flushed.


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