GFS: The Google File System
GFS: The Google File System GFS: The Google File System
What if Chunkserver Fails? • Master notices missing heartbeats • Master decrements count of replicas for all chunks on dead chunkserver • Master re-replicates chunks missing replicas in background – Highest priority for chunks missing greatest number of replicas 28
File Deletion • When client deletes file: – Master records deletion in its log – File renamed to hidden name including deletion timestamp • Master scans file namespace in background: – Removes files with such names if deleted for longer than 3 days (configurable) – In-memory metadata erased • Master scans chunk namespace in background: – Removes unreferenced chunks from chunkservers 29
- Page 1 and 2: GFS: The Google File System Michael
- Page 5 and 6: Google Platform Characteristics •
- Page 8 and 9: Google File System: Design Criteria
- Page 10 and 11: GFS: Architecture (2) 10
- Page 12 and 13: Chunkserver • Stores 64 MB file c
- Page 14 and 15: Client API • Not a filesystem in
- Page 16 and 17: Client Write • Some chunkserver i
- Page 18 and 19: Client Write (3) • All replicas a
- Page 20 and 21: Client Record Append (2) • When d
- Page 22 and 23: GFS: Consistency Model (2) • Chan
- Page 24 and 25: Applications and Record Append Sema
- Page 26 and 27: Chunk Leases and Version Numbers
- Page 30: Limitations • Security? - Trusted
- Page 37: Recovery Time • Experiment: kille
What if Chunkserver Fails?<br />
• Master notices missing heartbeats<br />
• Master decrements count of replicas for all<br />
chunks on dead chunkserver<br />
• Master re-replicates chunks missing<br />
replicas in background<br />
– Highest priority for chunks missing greatest<br />
number of replicas<br />
28
Change language