[FEATURE] Support dynamic cache PVC

[sunbinnnnn]

What feature you'd like to add:
User can only set cache SC on mountOptions, and CSI provision cache pv dynamically.

Why is this feature needed:
Most of block disk service doest not support readWriteMany, so that we can't use pvc cache no each node, and we must prepare pvc for now, it's hard to use in real production environment.

[zxh326]

If you want to implement this feature, consider writing a design draft first, such as how to configure cache size, when to create and when to delete, etc..

If Access Modes are configurable, would readWriteMany and readWriteOnce have distinct effects? would readWriteMany create a single PVC, whereas readWriteOnce creates one on each node?

[sunbinnnnn]

If you want to implement this feature, consider writing a design draft first, such as how to configure cache size, when to create and when to delete, etc..

If Access Modes are configurable, would readWriteMany and readWriteOnce have distinct effects? would readWriteMany create a single PVC, whereas readWriteOnce creates one on each node?

Thx for reply. Maybe use readWriteOnce by default（if user dose not provide existed PVC) and compatible with existed PVC or add a new option for that? Anyway, design is necessary for this feature.