You are viewing a plain text version of this content. The canonical link for it is here.

Posted to user@hbase.apache.org by Thomas Kwan <th...@manage.com> on 2014/09/26 16:02:52 UTC

Region Server on all data node?

Hi there,

To get good read performance, should the region server be installed on
every data node? (Thinking about data locality here)

thanks
thomas

Re: Region Server on all data node?

Posted by Ted Yu <yu...@gmail.com>.

Prior to major compaction, region server may need to read HFile(s) written
by other region server(s).
This could be due to region movement, etc.

Cheers

On Fri, Sep 26, 2014 at 11:43 AM, Thomas Kwan <th...@manage.com>
wrote:

> Thanks Ted for the pointer. A follow-up question.
>
> Will the region server always write data to its local hdfs? I am
> seeing logs that said the region server is trying to get data from
> another data nodes. Under what scenario will a region server needs to
> get data from a non-local data node?
>
> thanks
>
>
> On Fri, Sep 26, 2014 at 7:21 AM, Ted Yu <yu...@gmail.com> wrote:
> > Region server should be installed on server which is a data node.
> >
> > Region server count may be lower than data node count. So some data nodes
> > would not have region server running.
> >
> > See http://hbase.apache.org/book.html#regions.arch.locality
> >
> > Cheers
> >
> > On Fri, Sep 26, 2014 at 7:02 AM, Thomas Kwan <th...@manage.com>
> wrote:
> >
> >> Hi there,
> >>
> >> To get good read performance, should the region server be installed on
> >> every data node? (Thinking about data locality here)
> >>
> >> thanks
> >> thomas
> >>
>

Re: Region Server on all data node?

Posted by Thomas Kwan <th...@manage.com>.

Thanks Ted for the pointer. A follow-up question.

Will the region server always write data to its local hdfs? I am
seeing logs that said the region server is trying to get data from
another data nodes. Under what scenario will a region server needs to
get data from a non-local data node?

thanks

On Fri, Sep 26, 2014 at 7:21 AM, Ted Yu <yu...@gmail.com> wrote:
> Region server should be installed on server which is a data node.
>
> Region server count may be lower than data node count. So some data nodes
> would not have region server running.
>
> See http://hbase.apache.org/book.html#regions.arch.locality
>
> Cheers
>
> On Fri, Sep 26, 2014 at 7:02 AM, Thomas Kwan <th...@manage.com> wrote:
>
>> Hi there,
>>
>> To get good read performance, should the region server be installed on
>> every data node? (Thinking about data locality here)
>>
>> thanks
>> thomas
>>

Re: Region Server on all data node?

Posted by Ted Yu <yu...@gmail.com>.

Region server should be installed on server which is a data node.

Region server count may be lower than data node count. So some data nodes
would not have region server running.

See http://hbase.apache.org/book.html#regions.arch.locality

Cheers

On Fri, Sep 26, 2014 at 7:02 AM, Thomas Kwan <th...@manage.com> wrote:

> Hi there,
>
> To get good read performance, should the region server be installed on
> every data node? (Thinking about data locality here)
>
> thanks
> thomas
>