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 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 is
d use its
>> open() and read() calls to get the job done. Basically you would have to
>> force currentNode to be your node of interest in there.
>> Just curious, what is the use case for your request?
>>
>> Thanks,
>> Lohit
>>
>>
>>
>> --
e your node of interest in there.
> Just curious, what is the use case for your request?
>
> Thanks,
> Lohit
>
>
>
> - Original Message
> From: Kevin <[EMAIL PROTECTED]>
> To: "core-user@hadoop.apache.org"
> Sent: Tuesday, August 5, 2008 6:59:55 P
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 ou
s, what is the use case for your request?
>
> Thanks,
> Lohit
>
>
>
> - Original Message
> From: Kevin <[EMAIL PROTECTED]>
> To: "core-user@hadoop.apache.org"
> Sent: Tuesday, August 5, 2008 6:59:55 PM
> Subject: DFS. How to read from
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
Message
From: Kevin <[EMAIL PROTECTED]>
To: "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 want to r
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 from
