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From Michael Segel <michael_se...@hotmail.com>
Subject Re: HBASE -- Regionserver and QuorumPeer ?
Date Mon, 02 Jul 2012 14:46:43 GMT

I wasn't sure if St.Ack was displeased by my comments on Andrew's response, or my references
to KISS where the second S is stupid, reference to 'dead hookers' or reference to drugs. 
I was just covering my bases. :-)

With respect to Andrew's response, I saw something that I wasn't sure if I was reading too
much in to his response.  Hence my start with that I may be losing it because I was probably
reading something in to his response that he may not have intended. 

I guess its a problem many of us have, myself included, where we are sometimes intentionally
vague in our response. 

There are times when someone asks a question, the response is that they shouldn't do X, that
while its not a good idea to do something, its still theoretically possible to do. 
In this case running a RS and ZK on the same node.  Yes, it could be done with the proper
configuration where you isolate your disk I/O as much as possible between ZK and the RS. However
the better solution is to run the ZK along with the JT, NN, HM and even SN on the same node.
(For a small dev cluster.)

Another case in point is that we see things taken out of context. As an example, there was
a presentation by Facebook I think... where they run their HBase on nodes where they don't
run TT. In context, this could make a lot of sense when they are using HBase to deliver real
time response to an app outside of the cluster, and are not using it as part of a M/R job.
The problem is that someone sees this and takes it out of context saying that FB does it and
the best way to run HBase is to not run it on the same nodes you have TT running.  (Data Locality?
Forget about it...) 

Note I don't believe that this is what the FB presentation was suggesting except in their
specific solution. 

In another thread ,  someone was asking for help because they were having problems with their
cluster. One node was in India, Two were in the US. The response was along the idea that its
not a good thing to do this.   While I agree with the response, I have to wonder if it shouldn't
have been worded more strongly. We aren't saying it can't be done, we're saying that its not
something we'd recommend. I don't know if that's a strong enough response to really discourage
an OP from actually doing it. 

Is that a better explanation?

On Jul 2, 2012, at 6:53 AM, Mohammad Tariq wrote:

> What kind of explanation is this???????????
> Regards,
>    Mohammad Tariq
> On Mon, Jul 2, 2012 at 5:10 PM, Michael Segel <michael_segel@hotmail.com> wrote:
>> Sorry St. Ack,
>> Which is why I said that I was losing it...
>> The entire quote was...
>> "On Sun, Jul 1, 2012 at 2:05 PM, Jay Wilson
>> <registration@circle-cross-jn.com> wrote:
>>> Can a regionserver and quorumpeer reside on the same node?
>> It can, but you want to consider how disk is allocated in the cluster.
>> A typical and recommended configuration is HBase RegionServer and HDFS
>> DataNode colocated on the nodes. The DataNode will use locally
>> attached disk to store and serve blocks.
>> "
>> Looking at and parsing this you have two things...
>> 1) When reading the 'A typical and recommended configuration...' can imply that its
possible while not recommended to try and run an HBase RS while not running a DN service on
the same node.
>> 2) "It can, but you want to consider how disk is allocated in the cluster."
>> While on a single machine running as a pseudo cluster is one thing, running a fully
distributed cluster is another.
>> I am not finding fault with what Andy was saying. The problem is that we tend not
to use stronger language when discussing these topics.  And my point wasn't just on this topic
but others posts where we say 'not a good idea' yet someone still pursues the idea until there's
a chorus of saying not to do something.  I'm not faulting the poster because he wasn't and
isn't the only one who does this... We see it all the time where someone goes down the wrong
path, and is looking for a quick solution, rather than following the recommendation.
>> Now I'm not sure if my KISS statement or my 'dead hooker' analogy or my jokes about
>> KISS, I guess goes back to when I first learned that term. It was a 200 level Engineering
graphics course where the instructor mentioned KISS and then stalled on the second S (KIS
== Keep it Simple) and used the term 'Stupid' to refer back to the engineer who didn't keep
it simple. Of course he was the same Professor who couldn't figure out an algorithm without
using a GOTO statement and got huffy when I made the mistake of correcting him in class. 
(But that's another story.) Not sure if it should be KIS or if the second S in KISS was for
something else.
>> The 'dead hooker' analogy goes back to watching movie plots and subplots where the
hero wakes up next to a body of a dead woman in bed.  While in James Bond films its the evil
turned good hottie that gets it, I was thinking back to the Cameron Diaz flick 'Very Bad Things'
- 1998 movie where the plot line is based on a prostitute getting killed at a bachelor party.
Also for some reason the movie Barton Fink comes to mind, or the Great Gatsby.
>> And while I don't advocate drugs, that too is a reference to movies. Its the whole
'Airplane' spoofs where Lloyd Bridges talks about how today was a bad day for giving up  <insert
your favorite drug> ...
>> Sorry to side track but I thought I'd give a more detailed explanation ...
>> On Jul 2, 2012, at 2:51 AM, Stack wrote:
>>> On Mon, Jul 2, 2012 at 7:11 AM, Michael Segel <michael_segel@hotmail.com>
>>>> I'm sorry I'm losing it.
>>> Its plain.   Do us a favor and try keeping your psychotic breakdown to
>>> yourself going forward.
>>> St.Ack

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