Kevin wrote:
Thank you for the suggestion. I looked at DFSClient. It appears that
chooseDataNode method decides which data node to connect to. Currently
it chooses the first non-dead data node returned by namenode, which
have sorted the nodes by proximity to the client. However,
chooseDataNode
Yes, I agree with you that it should be negotiated. That is namenode
provides an ordered list and the client can choose some based on its
own measurements. But I am afraid 0.17.1 does not provide easy
interface for this.
-Kevin
On Thu, Aug 7, 2008 at 3:40 AM, Steve Loughran [EMAIL PROTECTED]
Kevin 写道:
Hi,
This is about dfs only, not to consider mapreduce. It may sound like a
strange need, but sometimes I want to read a block from a specific
data node which holds a replica. Figuring out which datanodes have the
block is easy. But is there an easy way to specify which datanode I
want
for your request?
Thanks,
Lohit
- Original Message
From: Kevin [EMAIL PROTECTED]
To: core-user@hadoop.apache.org core-user@hadoop.apache.org
Sent: Tuesday, August 5, 2008 6:59:55 PM
Subject: DFS. How to read from a specific datanode
Hi,
This is about dfs only, not to consider
Yes, the namenode is in charge of deciding the proximity by using
DNSToSwitchMapping. On the other hand, I am exploring the possibility
to let the client decide which data node to connect to, since
sometimes network hierarchy is so complex or dynamic that we better
leave it to the client to find
is the use case for your request?
Thanks,
Lohit
- Original Message
From: Kevin [EMAIL PROTECTED]
To: core-user@hadoop.apache.org core-user@hadoop.apache.org
Sent: Tuesday, August 5, 2008 6:59:55 PM
Subject: DFS. How to read from a specific datanode
Hi,
This is about dfs only
/CreateIssue!default.jspa) as
improvement request and continue the discussion there?
-Lohit
- Original Message
From: Kevin [EMAIL PROTECTED]
To: core-user@hadoop.apache.org
Sent: Wednesday, August 6, 2008 10:37:44 AM
Subject: Re: DFS. How to read from a specific datanode
Thank you
Hi,
This is about dfs only, not to consider mapreduce. It may sound like a
strange need, but sometimes I want to read a block from a specific
data node which holds a replica. Figuring out which datanodes have the
block is easy. But is there an easy way to specify which datanode I
want to load
Message
From: Kevin [EMAIL PROTECTED]
To: core-user@hadoop.apache.org core-user@hadoop.apache.org
Sent: Tuesday, August 5, 2008 6:59:55 PM
Subject: DFS. How to read from a specific datanode
Hi,
This is about dfs only, not to consider mapreduce. It may sound like a
strange need, but sometimes I
