XenServer/Overhead
Xen API driver overhead
Per-VM virtualization overhead calculations were added to the xenapi driver in this review: https://review.openstack.org/#/c/35380/
Data
The formula to calculate overhead is derived from the following data:
| XenServer version | VM type | VM memory size | VM memory overhead | Overhead/MB | Predicted Overhead |
|---|---|---|---|---|---|
| 6.0.0 | guest | 512.0 | 7.0 | 0.013671875 | 7.1472 |
| 6.0.0 | guest | 512.0 | 6.0 | 0.01171875 | 7.1472 |
| 6.0.0 | guest | 1024.0 | 11.0 | 0.0107421875 | 11.2944 |
| 6.0.0 | guest | 1024.0 | 10.0 | 0.009765625 | 11.2944 |
| 6.0.0 | guest | 2048.0 | 20.0 | 0.009765625 | 19.5888 |
| 6.0.0 | guest | 2048.0 | 19.0 | 0.00927734375 | 19.5888 |
| 6.0.0 | guest | 4096.0 | 36.0 | 0.0087890625 | 36.1776 |
| 6.0.0 | guest | 4096.0 | 35.0 | 0.008544921875 | 36.1776 |
| 6.0.0 | guest | 8192.0 | 70.0 | 0.008544921875 | 69.3552 |
| 6.0.0 | guest | 8192.0 | 69.0 | 0.0084228515625 | 69.3552 |
| 6.0.0 | guest | 15360.0 | 128.0 | 0.00833333333333 | 127.416 |
| 6.0.0 | guest | 15360.0 | 127.0 | 0.00826822916667 | 127.416 |
| 6.0.0 | guest | 30720.0 | 250.0 | 0.00813802083333 | 251.832 |
| 6.0.0 | guest | 30720.0 | 249.0 | 0.00810546875 | 251.832 |
