Why is my Amazon EBS volume stuck in the Optimizing state when I modify the volume?

Last updated: 2022-06-23

I modified my Amazon Elastic Block Store (Amazon EBS) volume. However, the process is either slow or appears to be stuck in the Optimizing state for a long time.

Short description

When you modify an Amazon EBS volume, the volume goes through a sequence of states. These volume states include the modifying state, the optimizing state, and finally the completed state.

If you increase the size of the volume, then the new size is available for use immediately after the modification. However, if the volume is in the Optimizing state, then the performance of the volume is in between the source and target configuration specifications. The performance of the volume is measured in terms of I/O operations per second and throughput.

Modifying an EBS volume can take from a few minutes to a few hours depending on the configuration changes being applied. An EBS volume of size 1 TiB can typically take up to 6 hours to be modified. However, the same volume might take 24 hours or longer in other situations. The time it takes for volumes to be modified doesn't always scale linearly. Therefore, a larger volume might take less time, and a smaller volume might take more time.


After a volume is modified, wait for at least six hours to modify the volume again. If the volume is still in the Optimizing state six hours after the modification, then you must wait until the volume completes the modification. If you must modify the volume while it's still in the Optimizing state, then use the following workaround solution:

  1. Use an Amazon EBS snapshot to restore a new EBS volume of the desired configurations. You can use an existing snapshot or create a new snapshot.
  2. Detach the current EBS volume that is in the Optimizing state.
  3. Attach the newly restored EBS volume to the instance, and use it thereafter.

Note: The new EBS volumes restored from snapshots must be initialized for achieving maximum performance.

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