The in-use - optimizing
state relates to EBS volume resizing.
in-use
indicates that this volume is attached to an EC2 instance.
optimizing
is the volume's modification state.
According to the AWS documentation on volume modifications:
An EBS volume being modified goes through a sequence of states. After you issue a ModifyVolume
directive, whether from the console, CLI, API, or SDK, the volume enters first the Modifying
state, then the Optimizing
state, and finally the Complete
state.
...
While the volume is in the optimizing state, your volume performance is in between the source and target configuration specifications. Transitional volume performance will be no less than the source volume performance. If you are downgrading IOPS, transitional volume performance is no less than the target volume performance.
And finally, from the introductory blog post for Volume Modifications:
The volume’s state reflects the progress of the operation (modifying, optimizing, or complete):
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…