[HDDS-1105] Add mechanism in Recon to obtain DB snapshot 'delta' updates from Ozone Manager.

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Labels: pull-request-available
• Target Version/s: 0.5.0
• Assignee: Aravindan Vijayan
• Reporter: Aravindan Vijayan
• Created: 14/Feb/19 14:21
• Updated: 19/Aug/19 17:51
• Resolved: 19/Aug/19 17:48

Description

Some context

The FSCK server will periodically invoke this OM API passing in the most recent sequence number of its own RocksDB instance. The OM will use the RockDB getUpdateSince() API to answer this query. Since the getUpdateSince API only works against the RocksDB WAL, we have to configure OM RocksDB WAL (https://github.com/facebook/rocksdb/wiki/Write-Ahead-Log) with sufficient max size to make this API useful. If the OM cannot get all transactions since the given sequence number (due to WAL flushing), it can error out. In that case the FSCK server can fall back to getting the entire checkpoint snapshot implemented in HDDS-1085.

Issue Links

• Blocked: HDDS-1085 Create an OM API to serve snapshots to Recon server
• duplicates: HDDS-1732 Add guice injection to Recon task framework.
• links to: GitHub Pull Request #1259