hadoop-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From jlei liu <liulei...@gmail.com>
Subject Re: HDFS-347 and HDFS-2246 issues different
Date Tue, 09 Oct 2012 06:52:10 GMT
Hi Harsh, thank you for your replay.

In HDFS-2246, when Local DataNode is dead, the DFSClient still can read
data form local file. I think that may lead to DFSCient read wrong data.
HDFS-347 use domain socket to implement Local Read, when Local DataNode is
dead, can DFSClient read data from local file?

Thanks,

LiuLei



2012/10/8 Harsh J <harsh@cloudera.com>

> As HDFS-2246 itself states in one comment:
>
> """
> HDFS-347 discusses ways to optimize reads for local clients. A clean
> design is fairly involved. A shortcut has been proposed where the
> client access the hdfs file blocks directly; this works if the client
> is the same user/group as the DN daemon. This is non-invasive and is a
> good short term solution till HDFS-347 is completed.
> """
>
> HDFS-347, when done, would not have the user/group limitation (you may
> call that a security/permissions problem as well), among other things.
> Going over the JIRA's comments should give you more insight :)
>
> On Mon, Oct 8, 2012 at 3:36 PM, jlei liu <liulei412@gmail.com> wrote:
> > The two issues both implement  DFSClient to directly open data blocks
> that
> > happen to be on the same machine function.  What are advantage of
>  HDFS-347?
> >
> > Thanks,
> >
> > LiuLei
>
>
>
> --
> Harsh J
>

Mime
View raw message