When the cluster capacity is almost full, make the cluster read only

[xu-chaojie]

1. When the space of a single chunkserver of curvebs is insufficient, do not directly down.
   The code is here：
   op_request.cpp, WriteChunkRequest::OnApply

and here:

2. It is necessary to make the cluster read-only when the cluster capacity is almost full, and restore the cluster to be readable and writable after waiting for the space to be free

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[NaturalSelect]

How can we know the space already to be free?

[liuminjian]

hello，i am a development engineer at chinatelecom cloud. I am very interested in cloud-native and storage systems. Can i try this?

[Subzeroo7]

How can we know the space already to be free?

Check the activity link. #2847
This issue has not yet been assigned.

[NaturalSelect]

Hello, I'm very interested in this issue, please let me try it.