From b56d66c5465b4e2eec438a5be0d5346c12cdf3be Mon Sep 17 00:00:00 2001 From: Chris Lu Date: Wed, 26 Jun 2019 22:21:38 -0700 Subject: [PATCH] Updated Erasure Coding for warm storage (markdown) --- Erasure-Coding-for-warm-storage.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Erasure-Coding-for-warm-storage.md b/Erasure-Coding-for-warm-storage.md index 5c8af3d..3b15c10 100644 --- a/Erasure-Coding-for-warm-storage.md +++ b/Erasure-Coding-for-warm-storage.md @@ -17,8 +17,8 @@ However, data can become warm or cold after a period of time. They are accessed The downside: * If some EC shards are missing, fetching data on those shards would be slower. * Re-construct missing EC shards would require transmitting whole volume data. -* current EC volumes can not have blob deletion as of now. The blob deletion is working in progress. -* Compaction would require transmitting whole volume data. +* Only deletion is supported. Update is not supported. +* Compaction is WIP. This would require transmitting whole volume data. ## Architecture SeaweedFS implemented 10.4 Reed-Soloman Erasure Coding (EC). The large volumes are split into chunks of 1GB, and every 10 data chunks are also encoded into 4 parity chunks. So a 30 GB data volume will be encoded into 14 EC shards, each shard is of size 3 GB and has 3 EC blocks.