Compute nodes have been sized with the total CPU and RAM capacity, but we did not cover the disk space capacity. Basically, there are many approaches to doing this, but it might expose other trade-offs: capacity and performance.
Storing instances' alternatives
External shared file storage
The disks of running instances are hosted externally and do not reside in compute nodes. This will have many advantages, such as the following:
- Ease of instance recovery in the case of compute - node failure
- Shared external storage for other installation purposes
On the other hand, it might present a few drawbacks, such as the following:
- Heavy I/O disk usage affecting the neighboring VM
- Performance degradation due to network latency
