[HDFS-16261] Configurable grace period around invalidation of replaced blocks

• Type: New Feature
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Labels: pull-request-available
• Assignee: Bryan Beaudreault
• Reporter: Bryan Beaudreault
• Created: 06/Oct/21 20:58
• Updated: 11/Dec/21 15:35

Description

When a block is moved with REPLACE_BLOCK, the new location is recorded in the NameNode and the NameNode instructs the old host to in invalidate the block using DNA_INVALIDATE. As it stands today, this invalidation is async but tends to happen relatively quickly.

I'm working on a feature for HBase which enables efficient healing of locality through Balancer-style low level block moves (HBASE-26250). One issue is that HBase tends to keep open long running DFSInputStreams and moving blocks from under them causes lots of warns in the RegionServer and increases long tail latencies due to the necessary retries in the DFSClient.

One way I'd like to fix this is to provide a configurable grace period on async invalidations. This would give the DFSClient enough time to refresh block locations before hitting any errors.

Issue Links

• relates to: HBASE-26250 Automatic and near real-time healing of locality
• links to: GitHub Pull Request #3594