Hello,

I read some articles which mention before the client connect to the
master node, he will first connect to the zookeeper node and find the
location of the root node. So, my question is that the node which
stores the root information is different from master node or they are
the same node?

Thanks!

Yong

To my knowledge, it is a three level tree-like structure.
 ------------------
该邮件从移动设备发送

------------------ Original ------------------
From: "yonghu"<[EMAIL PROTECTED]>
Date: Fri, Feb 10, 2012 07:12 PM
To: "user"<[EMAIL PROTECTED]>;
Subject: Which server store the root and .meta. information?
Hello,

I read some articles which mention before the client connect to the
master node, he will first connect to the zookeeper node and find the
location of the root node. So, my question is that the node which
stores the root information is different from master node or they are
the same node?

Thanks!

Yong

Thanks!
I know this. I just want to know which nodes store this information
when the client first contact to HBase cluster, HMaster or
RegionServer or a special node in which runs the zookeeper.

And the other question is whether zookeeper runs on the same nodes as
Hbase in the cluster or it  runs in a separate nodes?

Yong

On Fri, Feb 10, 2012 at 12:16 PM, Roger <[EMAIL PROTECTED]> wrote:
> To my knowledge, it is a three level tree-like structure.
>  ------------------
> 该邮件从移动设备发送
>
> ------------------ Original ------------------
> From: "yonghu"<[EMAIL PROTECTED]>
> Date: Fri, Feb 10, 2012 07:12 PM
> To: "user"<[EMAIL PROTECTED]>;
> Subject: Which server store the root and .meta. information?
>
>
> Hello,
>
> I read some articles which mention before the client connect to the
> master node, he will first connect to the zookeeper node and find the
> location of the root node. So, my question is that the node which
> stores the root information is different from master node or they are
> the same node?
>
> Thanks!
>
> Yong

The HMaster does not host regions, and the -ROOT- is a region; It is
hosted by one of the assigned RegionServers, and its location is
registered under ZooKeeper. The -ROOT- region then holds the location
of the .META. (Which again, is another region, and is hosted by
RegionServers in just the same way).

For your ZK question, if you run ZK in HBase's embedded mode, it runs
on the HMaster, while if you run it standalone you can choose to run
it anywhere. The latter method is what is recommended for production
deployments, and its preferable to host it separately on its own
boxes.

P.s. The JIRA at https://issues.apache.org/jira/browse/HBASE-3171 may
simplify this someday :)

2012/2/10 yonghu <[EMAIL PROTECTED]>:
> Thanks!
> I know this. I just want to know which nodes store this information
> when the client first contact to HBase cluster, HMaster or
> RegionServer or a special node in which runs the zookeeper.
>
> And the other question is whether zookeeper runs on the same nodes as
> Hbase in the cluster or it  runs in a separate nodes?
>
> Yong
>
> On Fri, Feb 10, 2012 at 12:16 PM, Roger <[EMAIL PROTECTED]> wrote:
>> To my knowledge, it is a three level tree-like structure.
>>  ------------------
>> 该邮件从移动设备发送
>>
>> ------------------ Original ------------------
>> From: "yonghu"<[EMAIL PROTECTED]>
>> Date: Fri, Feb 10, 2012 07:12 PM
>> To: "user"<[EMAIL PROTECTED]>;
>> Subject: Which server store the root and .meta. information?
>>
>>
>> Hello,
>>
>> I read some articles which mention before the client connect to the
>> master node, he will first connect to the zookeeper node and find the
>> location of the root node. So, my question is that the node which
>> stores the root information is different from master node or they are
>> the same node?
>>
>> Thanks!
>>
>> Yong

--
Harsh J
Customer Ops. Engineer
Cloudera | http://tiny.cloudera.com/about

Thanks for your reply. If the -ROOT- and .META. tables are managed by
two RegionServer separately. What is the functionality of Master node?
It only assigns the Region node in the cluster? So, the client only
needs to contact with these two special RegionServer which contains
the -ROOT- and .META. tables. If the interaction model is like what I
said, the client will not contact with master node!  If I am wrong,
let me know.

Thanks

Yong

On Fri, Feb 10, 2012 at 12:47 PM, Harsh J <[EMAIL PROTECTED]> wrote:
> The HMaster does not host regions, and the -ROOT- is a region; It is
> hosted by one of the assigned RegionServers, and its location is
> registered under ZooKeeper. The -ROOT- region then holds the location
> of the .META. (Which again, is another region, and is hosted by
> RegionServers in just the same way).
>
> For your ZK question, if you run ZK in HBase's embedded mode, it runs
> on the HMaster, while if you run it standalone you can choose to run
> it anywhere. The latter method is what is recommended for production
> deployments, and its preferable to host it separately on its own
> boxes.
>
> P.s. The JIRA at https://issues.apache.org/jira/browse/HBASE-3171 may
> simplify this someday :)
>
> 2012/2/10 yonghu <[EMAIL PROTECTED]>:
>> Thanks!
>> I know this. I just want to know which nodes store this information
>> when the client first contact to HBase cluster, HMaster or
>> RegionServer or a special node in which runs the zookeeper.
>>
>> And the other question is whether zookeeper runs on the same nodes as
>> Hbase in the cluster or it  runs in a separate nodes?
>>
>> Yong
>>
>> On Fri, Feb 10, 2012 at 12:16 PM, Roger <[EMAIL PROTECTED]> wrote:
>>> To my knowledge, it is a three level tree-like structure.
>>>  ------------------
>>> 该邮件从移动设备发送
>>>
>>> ------------------ Original ------------------
>>> From: "yonghu"<[EMAIL PROTECTED]>
>>> Date: Fri, Feb 10, 2012 07:12 PM
>>> To: "user"<[EMAIL PROTECTED]>;
>>> Subject: Which server store the root and .meta. information?
>>>
>>>
>>> Hello,
>>>
>>> I read some articles which mention before the client connect to the
>>> master node, he will first connect to the zookeeper node and find the
>>> location of the root node. So, my question is that the node which
>>> stores the root information is different from master node or they are
>>> the same node?
>>>
>>> Thanks!
>>>
>>> Yong
>
>
>
> --
> Harsh J
> Customer Ops. Engineer
> Cloudera | http://tiny.cloudera.com/about

The client does communicate with the master to perform .META. changing
interactions (create/delete tables, etc.). And for the rest, like
locating regions off regionservers and reading off them, the master
isn't touched (afaik).

The master's work is also more about running/providing cluster
management services for the many region servers than serving clients
all the while.

See the interfaces HMasterRegionInterface and MasterServices on trunk
to get a view of what all functions the master carries out, on a high
level, and why its role is important though clients may not need it
beyond administrative purposes.

2012/2/10 yonghu <[EMAIL PROTECTED]>:
> Thanks for your reply. If the -ROOT- and .META. tables are managed by
> two RegionServer separately. What is the functionality of Master node?
> It only assigns the Region node in the cluster? So, the client only
> needs to contact with these two special RegionServer which contains
> the -ROOT- and .META. tables. If the interaction model is like what I
> said, the client will not contact with master node!  If I am wrong,
> let me know.
>
> Thanks
>
> Yong
>
> On Fri, Feb 10, 2012 at 12:47 PM, Harsh J <[EMAIL PROTECTED]> wrote:
>> The HMaster does not host regions, and the -ROOT- is a region; It is
>> hosted by one of the assigned RegionServers, and its location is
>> registered under ZooKeeper. The -ROOT- region then holds the location
>> of the .META. (Which again, is another region, and is hosted by
>> RegionServers in just the same way).
>>
>> For your ZK question, if you run ZK in HBase's embedded mode, it runs
>> on the HMaster, while if you run it standalone you can choose to run
>> it anywhere. The latter method is what is recommended for production
>> deployments, and its preferable to host it separately on its own
>> boxes.
>>
>> P.s. The JIRA at https://issues.apache.org/jira/browse/HBASE-3171 may
>> simplify this someday :)
>>
>> 2012/2/10 yonghu <[EMAIL PROTECTED]>:
>>> Thanks!
>>> I know this. I just want to know which nodes store this information
>>> when the client first contact to HBase cluster, HMaster or
>>> RegionServer or a special node in which runs the zookeeper.
>>>
>>> And the other question is whether zookeeper runs on the same nodes as
>>> Hbase in the cluster or it  runs in a separate nodes?
>>>
>>> Yong
>>>
>>> On Fri, Feb 10, 2012 at 12:16 PM, Roger <[EMAIL PROTECTED]> wrote:
>>>> To my knowledge, it is a three level tree-like structure.
>>>>  ------------------
>>>> 该邮件从移动设备发送
>>>>
>>>> ------------------ Original ------------------
>>>> From: "yonghu"<[EMAIL PROTECTED]>
>>>> Date: Fri, Feb 10, 2012 07:12 PM
>>>> To: "user"<[EMAIL PROTECTED]>;
>>>> Subject: Which server store the root and .meta. information?
>>>>
>>>>
>>>> Hello,
>>>>
>>>> I read some articles which mention before the client connect to the
>>>> master node, he will first connect to the zookeeper node and find the
>>>> location of the root node. So, my question is that the node which
>>>> stores the root information is different from master node or they are
>>>> the same node?
>>>>
>>>> Thanks!
>>>>
>>>> Yong
>>
>>
>>
>> --
>> Harsh J
>> Customer Ops. Engineer
>> Cloudera | http://tiny.cloudera.com/about

--
Harsh J
Customer Ops. Engineer
Cloudera | http://tiny.cloudera.com/about

Also, there is a description of what is in META and ROOT in here...

http://hbase.apache.org/book.html#arch.catalog

... and it also describes the startup sequencing.

On 2/10/12 10:46 AM, "Harsh J" <[EMAIL PROTECTED]> wrote:

>The client does communicate with the master to perform .META. changing
>interactions (create/delete tables, etc.). And for the rest, like
>locating regions off regionservers and reading off them, the master
>isn't touched (afaik).
>
>The master's work is also more about running/providing cluster
>management services for the many region servers than serving clients
>all the while.
>
>See the interfaces HMasterRegionInterface and MasterServices on trunk
>to get a view of what all functions the master carries out, on a high
>level, and why its role is important though clients may not need it
>beyond administrative purposes.
>
>2012/2/10 yonghu <[EMAIL PROTECTED]>:
>> Thanks for your reply. If the -ROOT- and .META. tables are managed by
>> two RegionServer separately. What is the functionality of Master node?
>> It only assigns the Region node in the cluster? So, the client only
>> needs to contact with these two special RegionServer which contains
>> the -ROOT- and .META. tables. If the interaction model is like what I
>> said, the client will not contact with master node!  If I am wrong,
>> let me know.
>>
>> Thanks
>>
>> Yong
>>
>> On Fri, Feb 10, 2012 at 12:47 PM, Harsh J <[EMAIL PROTECTED]> wrote:
>>> The HMaster does not host regions, and the -ROOT- is a region; It is
>>> hosted by one of the assigned RegionServers, and its location is
>>> registered under ZooKeeper. The -ROOT- region then holds the location
>>> of the .META. (Which again, is another region, and is hosted by
>>> RegionServers in just the same way).
>>>
>>> For your ZK question, if you run ZK in HBase's embedded mode, it runs
>>> on the HMaster, while if you run it standalone you can choose to run
>>> it anywhere. The latter method is what is recommended for production
>>> deployments, and its preferable to host it separately on its own
>>> boxes.
>>>
>>> P.s. The JIRA at https://issues.apache.org/jira/browse/HBASE-3171 may
>>> simplify this someday :)
>>>
>>> 2012/2/10 yonghu <[EMAIL PROTECTED]>:
>>>> Thanks!
>>>> I know this. I just want to know which nodes store this information
>>>> when the client first contact to HBase cluster, HMaster or
>>>> RegionServer or a special node in which runs the zookeeper.
>>>>
>>>> And the other question is whether zookeeper runs on the same nodes as
>>>> Hbase in the cluster or it  runs in a separate nodes?
>>>>
>>>> Yong
>>>>
>>>> On Fri, Feb 10, 2012 at 12:16 PM, Roger <[EMAIL PROTECTED]> wrote:
>>>>> To my knowledge, it is a three level tree-like structure.
>>>>>  ------------------
>>>>> 该邮件从移动设备发送
>>>>>
>>>>> ------------------ Original ------------------
>>>>> From: "yonghu"<[EMAIL PROTECTED]>
>>>>> Date: Fri, Feb 10, 2012 07:12 PM
>>>>> To: "user"<[EMAIL PROTECTED]>;
>>>>> Subject: Which server store the root and .meta. information?
>>>>>
>>>>>
>>>>> Hello,
>>>>>
>>>>> I read some articles which mention before the client connect to the
>>>>> master node, he will first connect to the zookeeper node and find the
>>>>> location of the root node. So, my question is that the node which
>>>>> stores the root information is different from master node or they are
>>>>> the same node?
>>>>>
>>>>> Thanks!
>>>>>
>>>>> Yong
>>>
>>>
>>>
>>> --
>>> Harsh J
>>> Customer Ops. Engineer
>>> Cloudera | http://tiny.cloudera.com/about
>
>
>
>--
>Harsh J
>Customer Ops. Engineer
>Cloudera | http://tiny.cloudera.com/about
>

Hypothetical case (probably asked a number of time here, sorry...):

Can a client correcty put, get, scan (no admins tasks such as create
table,...) with a HBase cluster having its HMaster process down  ?

(if really the case, 'master' could be renamed to 'admin' to make it
clear that it is 'optional').

Thx,
Eric
On 10/02/12 20:00, Doug Meil wrote:
>
> Also, there is a description of what is in META and ROOT in here...
>
> http://hbase.apache.org/book.html#arch.catalog
>
> ... and it also describes the startup sequencing.
>
>
>
>
>
> On 2/10/12 10:46 AM, "Harsh J"<[EMAIL PROTECTED]>  wrote:
>
>> The client does communicate with the master to perform .META. changing
>> interactions (create/delete tables, etc.). And for the rest, like
>> locating regions off regionservers and reading off them, the master
>> isn't touched (afaik).
>>
>> The master's work is also more about running/providing cluster
>> management services for the many region servers than serving clients
>> all the while.
>>
>> See the interfaces HMasterRegionInterface and MasterServices on trunk
>> to get a view of what all functions the master carries out, on a high
>> level, and why its role is important though clients may not need it
>> beyond administrative purposes.
>>
>> 2012/2/10 yonghu<[EMAIL PROTECTED]>:
>>> Thanks for your reply. If the -ROOT- and .META. tables are managed by
>>> two RegionServer separately. What is the functionality of Master node?
>>> It only assigns the Region node in the cluster? So, the client only
>>> needs to contact with these two special RegionServer which contains
>>> the -ROOT- and .META. tables. If the interaction model is like what I
>>> said, the client will not contact with master node!  If I am wrong,
>>> let me know.
>>>
>>> Thanks
>>>
>>> Yong
>>>
>>> On Fri, Feb 10, 2012 at 12:47 PM, Harsh J<[EMAIL PROTECTED]>  wrote:
>>>> The HMaster does not host regions, and the -ROOT- is a region; It is
>>>> hosted by one of the assigned RegionServers, and its location is
>>>> registered under ZooKeeper. The -ROOT- region then holds the location
>>>> of the .META. (Which again, is another region, and is hosted by
>>>> RegionServers in just the same way).
>>>>
>>>> For your ZK question, if you run ZK in HBase's embedded mode, it runs
>>>> on the HMaster, while if you run it standalone you can choose to run
>>>> it anywhere. The latter method is what is recommended for production
>>>> deployments, and its preferable to host it separately on its own
>>>> boxes.
>>>>
>>>> P.s. The JIRA at https://issues.apache.org/jira/browse/HBASE-3171 may
>>>> simplify this someday :)
>>>>
>>>> 2012/2/10 yonghu<[EMAIL PROTECTED]>:
>>>>> Thanks!
>>>>> I know this. I just want to know which nodes store this information
>>>>> when the client first contact to HBase cluster, HMaster or
>>>>> RegionServer or a special node in which runs the zookeeper.
>>>>>
>>>>> And the other question is whether zookeeper runs on the same nodes as
>>>>> Hbase in the cluster or it  runs in a separate nodes?
>>>>>
>>>>> Yong
>>>>>
>>>>> On Fri, Feb 10, 2012 at 12:16 PM, Roger<[EMAIL PROTECTED]>  wrote:
>>>>>> To my knowledge, it is a three level tree-like structure.
>>>>>>   ------------------
>>>>>> 锟斤拷锟绞硷拷锟斤拷锟狡讹拷锟借备锟斤拷锟斤拷
>>>>>>
>>>>>> ------------------ Original ------------------
>>>>>> From: "yonghu"<[EMAIL PROTECTED]>
>>>>>> Date: Fri, Feb 10, 2012 07:12 PM
>>>>>> To: "user"<[EMAIL PROTECTED]>;
>>>>>> Subject: Which server store the root and .meta. information?
>>>>>>
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> I read some articles which mention before the client connect to the
>>>>>> master node, he will first connect to the zookeeper node and find the
>>>>>> location of the root node. So, my question is that the node which
>>>>>> stores the root information is different from master node or they are
>>>>>> the same node?
>>>>>>
>>>>>> Thanks!
>>>>>>
>>>>>> Yong
>>>>
>>>>
>>>>
>>>> --
>>>> Harsh J
>>>> Customer Ops. Engineer
>>>> Cloudera | http://tiny.cloudera.com/about

eric | http://about.echarles.net | @echarles

2012/2/11 Eric Charles <[EMAIL PROTECTED]>:
> Hypothetical case (probably asked a number of time here, sorry...):
>
> Can a client correcty put, get, scan (no admins tasks such as create
> table,...) with a HBase cluster having its HMaster process down  ?
>

It can Eric.   Kill your master and you can do all the above.
St.Ack

Funky, cause HBase is often presented as a 3-layers server model
zookeeper/master/region (root/meta in the regions bringing still more fogs).

Maybe the commonly understanding in the community is that HBase's
HMaster is like Hadoop's NameNode, which is not the case (NameNode's
failure will bring your cluster down, HMaster's failure will not...).

Upon presentation simplification (via 'master' renaming, or at least via
explanation emphases), having a more simple model such as the one
described in HBASE-3171 could help (this is my very short opinion, I
remember having read valid arguments against that model).

client<->zk<->(master)<->region(root|master)
or
client<->zk<->region (+admin)

the latter looks simpler, doesn't it?
Thx,

Eric

On 11/02/12 16:45, Stack wrote:
> 2012/2/11 Eric Charles<[EMAIL PROTECTED]>:
>> Hypothetical case (probably asked a number of time here, sorry...):
>>
>> Can a client correcty put, get, scan (no admins tasks such as create
>> table,...) with a HBase cluster having its HMaster process down  ?
>>
>
> It can Eric.   Kill your master and you can do all the above.
> St.Ack

--
eric | http://about.echarles.net | @echarles

Regarding the master being down, just be aware that if you lose an RS that
you'll have issues because the master is what does the reassignment.  Per
the previous comments, at steady-state HBase can run without the master -
there's an asterisk.
On 2/11/12 11:31 AM, "Eric Charles" <[EMAIL PROTECTED]> wrote:

>Funky, cause HBase is often presented as a 3-layers server model
>zookeeper/master/region (root/meta in the regions bringing still more
>fogs).
>
>Maybe the commonly understanding in the community is that HBase's
>HMaster is like Hadoop's NameNode, which is not the case (NameNode's
>failure will bring your cluster down, HMaster's failure will not...).
>
>Upon presentation simplification (via 'master' renaming, or at least via
>explanation emphases), having a more simple model such as the one
>described in HBASE-3171 could help (this is my very short opinion, I
>remember having read valid arguments against that model).
>
>client<->zk<->(master)<->region(root|master)
>or
>client<->zk<->region (+admin)
>
>the latter looks simpler, doesn't it?
>
>
>Thx,
>
>Eric
>
>On 11/02/12 16:45, Stack wrote:
>> 2012/2/11 Eric Charles<[EMAIL PROTECTED]>:
>>> Hypothetical case (probably asked a number of time here, sorry...):
>>>
>>> Can a client correcty put, get, scan (no admins tasks such as create
>>> table,...) with a HBase cluster having its HMaster process down  ?
>>>
>>
>> It can Eric.   Kill your master and you can do all the above.
>> St.Ack
>
>--
>eric | http://about.echarles.net | @echarles
>

Hi Doug,

I was well thinking that master was in the play in case of region split
or problems.
I searched in the paper book I have, but didn't really find anything on
that.

Luckily, it is well documented on
http://hbase.apache.org/book/regions.arch.html:

- failover: "... The Master will detect that the RegionServer has failed. "
- split: "...and then reports the split to the Master. "

So master seems also to be involved in a regular splitting in addition
to RS lose. More questions:

1.- What occurs if the region server can not report to Master after
splitting (for example if a guy like me killed the master to see 'what
happens'...).
2.- How does the master achieve the monitoring of its regions? (is there
an hearbeat generated by the regions or does Master pol).

(searched around in books... but didn't find, maybe something to do with
CatalogJanitor?)

Thx,
Eric

On 11/02/12 20:12, Doug Meil wrote:
>
> Regarding the master being down, just be aware that if you lose an RS that
> you'll have issues because the master is what does the reassignment.  Per
> the previous comments, at steady-state HBase can run without the master -
> there's an asterisk.
>
>
>
>
> On 2/11/12 11:31 AM, "Eric Charles"<[EMAIL PROTECTED]>  wrote:
>
>> Funky, cause HBase is often presented as a 3-layers server model
>> zookeeper/master/region (root/meta in the regions bringing still more
>> fogs).
>>
>> Maybe the commonly understanding in the community is that HBase's
>> HMaster is like Hadoop's NameNode, which is not the case (NameNode's
>> failure will bring your cluster down, HMaster's failure will not...).
>>
>> Upon presentation simplification (via 'master' renaming, or at least via
>> explanation emphases), having a more simple model such as the one
>> described in HBASE-3171 could help (this is my very short opinion, I
>> remember having read valid arguments against that model).
>>
>> client<->zk<->(master)<->region(root|master)
>> or
>> client<->zk<->region (+admin)
>>
>> the latter looks simpler, doesn't it?
>>
>>
>> Thx,
>>
>> Eric
>>
>> On 11/02/12 16:45, Stack wrote:
>>> 2012/2/11 Eric Charles<[EMAIL PROTECTED]>:
>>>> Hypothetical case (probably asked a number of time here, sorry...):
>>>>
>>>> Can a client correcty put, get, scan (no admins tasks such as create
>>>> table,...) with a HBase cluster having its HMaster process down  ?
>>>>
>>>
>>> It can Eric.   Kill your master and you can do all the above.
>>> St.Ack
>>
>> --
>> eric | http://about.echarles.net | @echarles
>>
>
>

--
eric | http://about.echarles.net | @echarles

Hi there-

Glad to hear that the Arch chapter was helpful!

re:  #1 "splits"

The split won't be complete if the master isn't there.  Good question, and
the effects of the master not being up will be added to the book.

re:  #2. "RS monitoring"

Good question, I'm not familiar with the specifics on that.   (and more
info will be added to the book too.)

On 2/12/12 4:00 AM, "Eric Charles" <[EMAIL PROTECTED]> wrote:

>Hi Doug,
>
>I was well thinking that master was in the play in case of region split
>or problems.
>I searched in the paper book I have, but didn't really find anything on
>that.
>
>Luckily, it is well documented on
>http://hbase.apache.org/book/regions.arch.html:
>
>- failover: "... The Master will detect that the RegionServer has failed.
>"
>- split: "...and then reports the split to the Master. "
>
>So master seems also to be involved in a regular splitting in addition
>to RS lose. More questions:
>
>1.- What occurs if the region server can not report to Master after
>splitting (for example if a guy like me killed the master to see 'what
>happens'...).
>2.- How does the master achieve the monitoring of its regions? (is there
>an hearbeat generated by the regions or does Master pol).
>
>(searched around in books... but didn't find, maybe something to do with
>CatalogJanitor?)
>
>Thx,
>Eric
>
>On 11/02/12 20:12, Doug Meil wrote:
>>
>> Regarding the master being down, just be aware that if you lose an RS
>>that
>> you'll have issues because the master is what does the reassignment.
>>Per
>> the previous comments, at steady-state HBase can run without the master
>>-
>> there's an asterisk.
>>
>>
>>
>>
>> On 2/11/12 11:31 AM, "Eric Charles"<[EMAIL PROTECTED]>  wrote:
>>
>>> Funky, cause HBase is often presented as a 3-layers server model
>>> zookeeper/master/region (root/meta in the regions bringing still more
>>> fogs).
>>>
>>> Maybe the commonly understanding in the community is that HBase's
>>> HMaster is like Hadoop's NameNode, which is not the case (NameNode's
>>> failure will bring your cluster down, HMaster's failure will not...).
>>>
>>> Upon presentation simplification (via 'master' renaming, or at least
>>>via
>>> explanation emphases), having a more simple model such as the one
>>> described in HBASE-3171 could help (this is my very short opinion, I
>>> remember having read valid arguments against that model).
>>>
>>> client<->zk<->(master)<->region(root|master)
>>> or
>>> client<->zk<->region (+admin)
>>>
>>> the latter looks simpler, doesn't it?
>>>
>>>
>>> Thx,
>>>
>>> Eric
>>>
>>> On 11/02/12 16:45, Stack wrote:
>>>> 2012/2/11 Eric Charles<[EMAIL PROTECTED]>:
>>>>> Hypothetical case (probably asked a number of time here, sorry...):
>>>>>
>>>>> Can a client correcty put, get, scan (no admins tasks such as create
>>>>> table,...) with a HBase cluster having its HMaster process down  ?
>>>>>
>>>>
>>>> It can Eric.   Kill your master and you can do all the above.
>>>> St.Ack
>>>
>>> --
>>> eric | http://about.echarles.net | @echarles
>>>
>>
>>
>
>--
>eric | http://about.echarles.net | @echarles
>