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https://issues.apache.org/jira/browse/HDFS-5442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13856232#comment-13856232
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LiuLei commented on HDFS-5442:
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Hi Jerry Chen,
Thanks for your your detailed answer.
I have bloew questions:
1. If I want store three replicas in secondary cluster. With synchronous data
writing, does the primary cluster need to maintain NetworkTopology of datanodes
in secondary cluster?
2. If the active namenode of secondary cluster has not received heartbeat msg
from a datanode for more than 30s , the datanode will be marked and treated
as "stale" default. These stale datanodes will be not written data. When
datanodes in secondary cluster is become "stale", does the active namenode of
secondary cluster send DR_DN_AVAILABLE command to namenodes in primary cluster?
And when the "stale" is become lived, does the active namenode of secondary
cluster send DR_DN_AVAILABLE command to namenodes in primary cluster?
3. When secondary cluster become primary cluster, can the client automatically
switch to secondary cluster?
> Zero loss HDFS data replication for multiple datacenters
> --------------------------------------------------------
>
> Key: HDFS-5442
> URL: https://issues.apache.org/jira/browse/HDFS-5442
> Project: Hadoop HDFS
> Issue Type: Improvement
> Reporter: Avik Dey
> Attachments: Disaster Recovery Solution for Hadoop.pdf, Disaster
> Recovery Solution for Hadoop.pdf
>
>
> Hadoop is architected to operate efficiently at scale for normal hardware
> failures within a datacenter. Hadoop is not designed today to handle
> datacenter failures. Although HDFS is not designed for nor deployed in
> configurations spanning multiple datacenters, replicating data from one
> location to another is common practice for disaster recovery and global
> service availability. There are current solutions available for batch
> replication using data copy/export tools. However, while providing some
> backup capability for HDFS data, they do not provide the capability to
> recover all your HDFS data from a datacenter failure and be up and running
> again with a fully operational Hadoop cluster in another datacenter in a
> matter of minutes. For disaster recovery from a datacenter failure, we should
> provide a fully distributed, zero data loss, low latency, high throughput and
> secure HDFS data replication solution for multiple datacenter setup.
> Design and code for Phase-1 to follow soon.
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