You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@hbase.apache.org by mail list <lo...@gmail.com> on 2014/11/08 11:44:57 UTC
Question about hbase's name node
hi all,
We are testing the HBase. We shutdown all the name nodes,
but we can still put rows into HBase, and the “list” command is blocking.
Then we stop and restart all the HBase system, the rows which were put before
is persistent.
So i want to know if the name node goes wrong, the HBase can handle “put” command?
Am i right? and why ?
Any idea will be appreciated!!
Re: Question about hbase's name node
Posted by David DENG <da...@gmail.com>.
Check the block size of HDFS not HBase cache block size. When you make a
put, data is written to HLog and memstore.
David
On Sat, Nov 8, 2014 at 6:13 PM, mail list <lo...@gmail.com> wrote:
> Hi David,
>
> Thanks for your reply.
> The default block size is 64K, So you mean that after i write enough rows
> which exceeds the block size, then
> the put command will not success?
>
>
> On Nov 9, 2014, at 4:14, David <da...@gmail.com> wrote:
>
> > The region server only need to talk to name ode when the current block
> is done
> >
> > Sent from my iPhone
> >
> >> On Nov 8, 2014, at 02:44, mail list <lo...@gmail.com> wrote:
> >>
> >> hi all,
> >>
> >> We are testing the HBase. We shutdown all the name nodes,
> >> but we can still put rows into HBase, and the “list” command is
> blocking.
> >> Then we stop and restart all the HBase system, the rows which were put
> before
> >> is persistent.
> >>
> >> So i want to know if the name node goes wrong, the HBase can handle
> “put” command?
> >> Am i right? and why ?
> >>
> >> Any idea will be appreciated!!
> >>
>
>
Re: Question about hbase's name node
Posted by mail list <lo...@gmail.com>.
Or the WAL write exceed the block size ?
On Nov 9, 2014, at 10:13, mail list <lo...@gmail.com> wrote:
> Hi David,
>
> Thanks for your reply.
> The default block size is 64K, So you mean that after i write enough rows which exceeds the block size, then
> the put command will not success?
>
>
> On Nov 9, 2014, at 4:14, David <da...@gmail.com> wrote:
>
>> The region server only need to talk to name ode when the current block is done
>>
>> Sent from my iPhone
>>
>>> On Nov 8, 2014, at 02:44, mail list <lo...@gmail.com> wrote:
>>>
>>> hi all,
>>>
>>> We are testing the HBase. We shutdown all the name nodes,
>>> but we can still put rows into HBase, and the “list” command is blocking.
>>> Then we stop and restart all the HBase system, the rows which were put before
>>> is persistent.
>>>
>>> So i want to know if the name node goes wrong, the HBase can handle “put” command?
>>> Am i right? and why ?
>>>
>>> Any idea will be appreciated!!
>>>
>
Re: Question about hbase's name node
Posted by mail list <lo...@gmail.com>.
Lots thanks to David and Sean Busbey, I got it.
On Nov 9, 2014, at 10:58, Sean Busbey <bu...@cloudera.com> wrote:
> On Sat, Nov 8, 2014 at 8:13 PM, mail list <lo...@gmail.com> wrote:
>
>> Hi David,
>>
>> Thanks for your reply.
>> The default block size is 64K, So you mean that after i write enough rows
>> which exceeds the block size, then
>> the put command will not success?
>>
>>
>>
> What version of HDFS? The default block size has been 128MB for all of
> Hadoop 2.x and was 64MB for Hadoop 1.x.
>
> The write ahead log will attempt to roll when you get to 95% of this size
> (unless you have changed either the default block size or configured an
> alternative write ahead log block size). That will require interaction with
> the NameNode.
>
> --
> Sean
Re: Question about hbase's name node
Posted by Sean Busbey <bu...@cloudera.com>.
On Sat, Nov 8, 2014 at 8:13 PM, mail list <lo...@gmail.com> wrote:
> Hi David,
>
> Thanks for your reply.
> The default block size is 64K, So you mean that after i write enough rows
> which exceeds the block size, then
> the put command will not success?
>
>
>
What version of HDFS? The default block size has been 128MB for all of
Hadoop 2.x and was 64MB for Hadoop 1.x.
The write ahead log will attempt to roll when you get to 95% of this size
(unless you have changed either the default block size or configured an
alternative write ahead log block size). That will require interaction with
the NameNode.
--
Sean
Re: Question about hbase's name node
Posted by mail list <lo...@gmail.com>.
Hi David,
Thanks for your reply.
The default block size is 64K, So you mean that after i write enough rows which exceeds the block size, then
the put command will not success?
On Nov 9, 2014, at 4:14, David <da...@gmail.com> wrote:
> The region server only need to talk to name ode when the current block is done
>
> Sent from my iPhone
>
>> On Nov 8, 2014, at 02:44, mail list <lo...@gmail.com> wrote:
>>
>> hi all,
>>
>> We are testing the HBase. We shutdown all the name nodes,
>> but we can still put rows into HBase, and the “list” command is blocking.
>> Then we stop and restart all the HBase system, the rows which were put before
>> is persistent.
>>
>> So i want to know if the name node goes wrong, the HBase can handle “put” command?
>> Am i right? and why ?
>>
>> Any idea will be appreciated!!
>>
Re: Question about hbase's name node
Posted by David <da...@gmail.com>.
The region server only need to talk to name ode when the current block is done
Sent from my iPhone
> On Nov 8, 2014, at 02:44, mail list <lo...@gmail.com> wrote:
>
> hi all,
>
> We are testing the HBase. We shutdown all the name nodes,
> but we can still put rows into HBase, and the “list” command is blocking.
> Then we stop and restart all the HBase system, the rows which were put before
> is persistent.
>
> So i want to know if the name node goes wrong, the HBase can handle “put” command?
> Am i right? and why ?
>
> Any idea will be appreciated!!
>
Re: Question about hbase's name node
Posted by Dima Spivak <ds...@cloudera.com>.
bcc: dev@, cc: user@
On Sat, Nov 8, 2014 at 2:44 AM, mail list <lo...@gmail.com> wrote:
> hi all,
>
> We are testing the HBase. We shutdown all the name nodes,
> but we can still put rows into HBase, and the “list” command is
> blocking.
> Then we stop and restart all the HBase system, the rows which were put
> before
> is persistent.
>
> So i want to know if the name node goes wrong, the HBase can handle
> “put” command?
> Am i right? and why ?
>
> Any idea will be appreciated!!
>
>
Re: Question about hbase's name node
Posted by Dima Spivak <ds...@cloudera.com>.
bcc: dev@, cc: user@
On Sat, Nov 8, 2014 at 2:44 AM, mail list <lo...@gmail.com> wrote:
> hi all,
>
> We are testing the HBase. We shutdown all the name nodes,
> but we can still put rows into HBase, and the “list” command is
> blocking.
> Then we stop and restart all the HBase system, the rows which were put
> before
> is persistent.
>
> So i want to know if the name node goes wrong, the HBase can handle
> “put” command?
> Am i right? and why ?
>
> Any idea will be appreciated!!
>
>