hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Lucas Stanley <lucas23...@gmail.com>
Subject HBase failure scenarios
Date Tue, 11 Jun 2013 00:26:39 GMT
Hi,

In the Strata 2013 training lectures, Jonathan Hsieh from Cloudera said
something about HBase syncs which I'm trying to understand further.

He said that HBase sync guarantees only that a write goes to the local disk
on the region server responsible for that region and in-memory copies go on
2 other machines in the HBase cluster.

But I thought that when the write goes to the WAL on the first region
server, that the HDFS append would push that write to 3 machines total in
the HDFS cluster. In order for the append write to the WAL to be
successful, doesn't the DataNode on that machine have to pipeline the write
to 2 other DataNodes?

I'm not sure what Jonathan was referring to when he said that 2 in-memory
copies go to other HBase machines? Even when the memstore on the first
region server gets full, doesn't the flush to the HFile get written on 3
HDFS nodes in total?

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message