This post illustrates the steps about how to increase KVM guest memory. If the current KVM guest memory is the same as the memory limit, you can to increase the memory offline following the below steps:
1. Check the current memory status of the KVM guest:
[root@kvm-host]# virsh dumpxml kvm-guest | grep -i memory <memory unit='KiB'>8392704</memory> ### the maximum amount of memory that can be allocated to the VM <currentMemory unit='KiB'>8392704</currentMemory> ### current Guest VM memory
[root@kvm-host]# virsh dominfo kvm-guest Id: 12 Name: kvm-guest UUID: 8f6fc48c-a6f4-429d-b77e-88a4b8d3d961 OS Type: hvm State: running CPU(s): 4 CPU time: 429.8s Max memory: 8392704 KiB Used memory: 8392704 KiB Persistent: yes Autostart: disable Managed save: no Security model: selinux Security DOI: 0 Security label: system_u:system_r:svirt_t:s0:c339,c981 (enforcing)
[root@kvm-host]# virsh dominfo kvm-guest Id: 12 Name: kvm-guest UUID: 8f6fc48c-a6f4-429d-b77e-88a4b8d3d961 OS Type: hvm State: running CPU(s): 4 CPU time: 429.8s Max memory: 8392704 KiB Used memory: 8392704 KiB Persistent: yes Autostart: disable Managed save: no Security model: selinux Security DOI: 0 Security label: system_u:system_r:svirt_t:s0:c339,c981 (enforcing)
2. Shutdown the Guest VM:
[root@kvm-host]# virsh list Id Name State ---------------------------------------------------- 12 kvm-guest running
[root@kvm-host]# virsh destroy kvm-guest Domain kvm-guest destroyed
[root@kvm-host]# virsh list Id Name State ----------------------------------------------------
3. Update the memory:
# virsh edit guest_vm
For example:
[root@kvm-host]# virsh edit kvm-guest Domain kvm-guest XML configuration edited.
From:
<memory unit='KiB'>8392704</memory> <currentMemory unit='KiB'>8392704</currentMemory>
To:
<memory unit='KiB'>16777216</memory> <currentMemory unit='KiB'>16777216</currentMemory>
4. Boot the Guest VM:
[root@kvm-host]# virsh start kvm-guest Domain kvm-guest started
5. Check if the memory has been increased:
From KVM host:
[root@kvm-host]# virsh dominfo kvm-guest ... Name: kvm-guest UUID: 8f6fc48c-a6f4-429d-b77e-88a4b8d3d961 Max memory: 16777216 KiB Used memory: 16777216 KiB ...
[root@kvm-host]# virsh dumpxml kvm-guest |grep -i memo <memory unit='KiB'>16777216</memory> <currentMemory unit='KiB'>16777216</currentMemory>
From guest:
[root@localhost ~]# free -g total used free shared buffers cached Mem: 15 0 15 0 0 0 -/+ buffers/cache: 0 15 Swap: 3 0 3