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https://issues.apache.org/jira/browse/HDDS-13003?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Siyao Meng updated HDDS-13003:
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    Summary: Snapshot Defragmentation to reduce storage footprint  (was: 
Snapshot Compaction to reduce storage footprint)

> Snapshot Defragmentation to reduce storage footprint
> ----------------------------------------------------
>
>                 Key: HDDS-13003
>                 URL: https://issues.apache.org/jira/browse/HDDS-13003
>             Project: Apache Ozone
>          Issue Type: Improvement
>          Components: Ozone Manager
>            Reporter: Swaminathan Balachandran
>            Assignee: Swaminathan Balachandran
>            Priority: Major
>              Labels: pull-request-available
>
> In Apache Ozone, snapshots currently take a checkpoint of the Active Object 
> Store (AOS) RocksDB each time a snapshot is created and track the compaction 
> of SST files over time. This model works efficiently when snapshots are 
> short-lived, as they merely serve as hard links to the AOS RocksDB. However, 
> over time, if an older snapshot persists while significant churn occurs in 
> the AOS RocksDB (due to compactions and writes), the snapshot RocksDB may 
> diverge significantly from both the AOS RocksDB and other snapshot RocksDB 
> instances. This divergence increases storage requirements linearly with the 
> number of snapshots.
> The primary inefficiency in the current snapshotting mechanism stems from 
> constant RocksDB compactions in AOS, which can cause a key, file, or 
> directory entry to appear in multiple SST files. Ideally, each unique key, 
> file, or directory entry should reside in only one SST file, eliminating 
> redundant storage and mitigating the multiplier effect caused by snapshots. 
> If implemented correctly, the total RocksDB size would be proportional to the 
> total number of unique keys in the system rather than the number of snapshots.
>  



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