How to Increase Memory in Xen Vm

For Example, Here you want to increase memory from 6GB to 12GB.

Login to the Xen Host as root user and check the VM maximum memory settings. If Maximum memory setting is not more than equal to Target memory follow the below steps.

[root@Xenhost ~]# virsh dumpxml xenvm100 | grep -i mem
  <memory>6291456</memory>    -----------------> Here Memory settings in KB
  <currentMemory>6291456</currentMemory>

This shows that it has 6 GB currently in use. And that max memory is set to 6GB. Therefore we need server downtime for increase to 12GB

So, the procedure will be:

1. virsh setmem xenvm100 12582912
2. vi /etc/xen/xenvm100
   2a. change "memory = 12288" to "memory = 12288"  ------> Here in MB
   2b. save config
 
Reboot the VM and check the memory.

Hope it will help.