Finding out via librados if a cluster is near full

[Wido den Hollander <wido@42on.com>]

Hi,

Is there a way to find out if a cluster is near full via librados?

The reason I'm asking is that I'm working on a deployment of the RADOS 
Gateway and one of the potential problems I see is that the RADOS 
Gateway can keep writing and filling up the whole cluster.

It's obvious that it's the admin's responsibility to make sure that 
doesn't happen, but what I'd like to do is make the RADOS Gateway deny 
PUT requests when the cluster is near full.

That way normal meta data operations (thus writes) can continue, but new 
objects won't be accepted until the cluster has enough space available.

This might also be useful for librbd. Refuse the creation of new RBD 
images so that existing images can continue operating.

-- 
Wido den Hollander
42on B.V.

Phone: +31 (0)20 700 9902
Skype: contact42on