[HDFS-3544] Ability to use SimpleRegeratingCode to fix missing blocks

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Won't Fix
• Component/s: contrib/raid
• Assignee: Unassigned
• Reporter: Dhruba Borthakur
• Created: 05/Nov/11 18:22
• Updated: 07/Oct/16 20:34
• Resolved: 07/Oct/16 20:31

Description

ReedSolomon encoding (n, k) has n storage nodes and can tolerate n-k failures. Regenerating a block needs to access k blocks. This is a problem when n and k are large. Instead, we can use simple regenerating codes (n, k, f) that does first does ReedSolomon (n,k) and then does XOR with f stripe size. Then, a single disk failure needs to access only f nodes and f can be very small.

Issue Links

• depends upon: HDFS-3543 Refactor Raid so it can work better with new erasure codes