Question
Limits and restrictions for virtual server creation
Answer
There are no hard limits and restrictions for the virtual servers’ creation in the OnApp Cloud, but we recommend following the next recommendation for the best performance:
CPU - it is possible to over-commit CPU cores. Based on current recommendations for KVM and XEN, we suggest not using more than 5x overcommit of virtual to real CPU load.
Memory - you can over-provision memory and the total amount of memory used in Dom0. The storage controllers and your virtual servers can not exceed the hypervisors’ RAM.
VDisk density - the limits on VDisk density depend on the amount of RAM provided by the storage controller, the datastore configuration and the types of VMs you are creating.
IP addresses:
- The maximum number of IPs you can add to a VS based on XEN 4 hypervisor is 301.
- The maximum number of IPs you can add to a VS based on KVM hypervisor under Centos6 is 700.
Network interfaces: The maximum number of dummy network interfaces added to XEN 4/KVM 6 hypervisor which has been tested is 10.
For hypervisor limitations, see the following article:
http://www.redhat.com/resourcelibrary/articles/virtualization-limits-rhel-hypervisors