ChenSammi commented on code in PR #9858: URL: https://github.com/apache/ozone/pull/9858#discussion_r2894501498
########## hadoop-hdds/docs/content/design/diskbalancer.md: ########## @@ -120,16 +120,11 @@ and balanced state will be visible only after the configured delay, when the sou By default, the DiskBalancer uses specific policies to decide which disks to balance and which containers to move. These are configurable, but the default implementations provide robust and safe behavior. -* **`DefaultVolumeChoosingPolicy`**: This is the default policy for selecting the source and destination volumes. It -identifies the most over-utilized volume as the source and the most under-utilized volume as the destination by comparing -each volume's utilization against the Datanode's average. The calculation is smart enough to account for data that is -already in the process of being moved, ensuring it makes accurate decisions based on the future state of the volumes. - -* **`DefaultContainerChoosingPolicy`**: This is the default policy for selecting which container to move from a source -volume. It iterates through the containers on the source disk and picks the first one that is in a **CLOSED** state -and is not already being moved by another balancing operation. To optimize performance and avoid re-scanning the same -containers repeatedly, it caches the list of containers for each volume which auto expires after one hour of its last -used time or if the container iterator for that is invalidated on full utilisation. +* **`DefaultVolumeContainerChoosingPolicy`**: This is the default policy that consolidates both volume selection and container +selection into a single operation. It identifies the most over-utilized volume as the source and the most under-utilized +volume with sufficient space as the destination, then iterates through containers on the source to pick the first one +that is in a **CLOSED** state and is not already being moved. Consolidating both steps avoids recalculating ideal Review Comment: We don't need to explain why we consolidate the two policies in a final doc, it's a low level implementation detail. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
