hadoop-common-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Harsh J <ha...@cloudera.com>
Subject Re: Re: how to select the position of a block
Date Wed, 07 Dec 2011 20:08:12 GMT
Yep, its been moved to a different area after pluggable block
placement policies were introduced. I answered with RTC cause OP was
reading the hadoop book, which surrounds what is today 1.0.

2011/12/7 Praveen Sripati <praveensripati@gmail.com>:
> Not sure why, but I was able to find ReplicationTargetChooser.java only in
> branch-1.0 and not in trunk, 21, 22 and 23.
> Regards,
> Praveen
> 2011/12/7 郭冲 <guochonghenu@126.com>
>> isGoodTarget() in  ReplicationTargetChooser.java  judge if a node is a
>> good node, it will consider the disk space , load , and the rack which it
>> located has too much nodes or not .Thanks!
>> At 2011-12-07 13:01:26,"Harsh J" <harsh@cloudera.com> wrote:
>> >Moving discussion to hdfs-dev.
>> >
>> >DataNodes report disk usage (space) and current transfer thread counts
>> (load) periodically to the NameNode. NameNode uses this information to make
>> a decision while building the pipeline DNs for your client request. I
>> believe the class is called something like ReplicationTargetChooser (off
>> the top of my mind), and you can take a look at the logic involved there in
>> selecting any form of node (isGoodTarget or summat). Then work your way
>> downwards to see how the information flows.
>> >
>> >On 07-Dec-2011, at 8:36 AM, 郭冲 wrote:
>> >
>> >> Hadoop:The Definitive Guide  said that when the client is out of the
>> cluster, hadoop will select the storage position of a block randomly,but it
>> will not select the datanode which is too busy or too full.
>> >>
>> >> so i want to kown that  how hadoop judge or measure a datanode is full
>> or not?
>> >

Harsh J

View raw message