RAC interview qstns

Recently attended RAC interview, few qstns are here..
1.what happens if Oracle Cluster Filessystem crashes?
2.after adding a node in Ebusiness suite, what steps to be taken to get that new node registered.
3.what is the main diff between RAC -RAC and RAC to NonRAC (I mean which clone step makes this difference)?
4.How DDL changes takes place in RAC (assume you have 6 node and at what stage ddl change will get registered)
Edited by: user11971355 on Apr 28, 2010 2:06 PM

Not really sensible questions. Take the 1st one - "+what happens if Oracle Cluster Filessystem crashes?+"
Nothing.. unless one is unlucky/silly enough to still use ocfs as shared storage - and not ASM. If ocfs is used as shared cluster mount for sharing external data (e.g CSV) files, then worse is that UTL_FILE will fail or an external table will fail.
Also, why would ocfs fail? IMO it is far more important to understand the components on which ocfs relies - and how these impact ocfs. Especially as these underlying components can also impact Grid/CRS and RAC too.

Similar Messages

Interview qstns..??

Hi Gurus,
i am posting some of the interview qstns aked in one of the top MNC's last week...
pls any one reply me answers to these qstns...
full points will be assigned ....
a little explanation will be highly appreciated..
here are the questions...
1. What is table partition?
2. What are the options available in transfer rule and when ABAP code is recquired during the transfer rule what important variables you can use?
3. How would you optimize the dimensions?
4. What are the conversion routines for units and currencies in the update rule?
5. Can you make an infoobject as info provider and why?
6. What are the steps to unload non cumulative cubes?
7. Give step to step approach to archiving cubex.
8. What are the load process and post processing.
9. What are the data target administration task
10. What are the parallel process that could have locking problems
11. How would you convert a info package group into a process chain?
12. How do you transoform Open Hub Data?
13. What are the data loading tuning one can do?
awaiting ur replies...
thanks in advance
cheers
Prince

hi prince,
Answers:
3) Optimizing Dimensions: It can be done by creating as many dimensions as possible. More importantly we have to make sure that a single dimension should never exceed his size more than 20% of fact table.
5) If we want to extract report as per characteristics then we can convert the infoObject to an datatarget(infoProvider). Procedure is Rt. Click on InfoObject and select "Insert Characteristic as DataTarget".
Hope it helps u
thanks===points
ramana

RAC Interview Questions

Hi All
i am a newbie in RAC and wants to appear in RAC Job Interviews.
Pls give me questions which you have ever asked.
Regards
Naveen Chhibber

Hi Naveenchhibber,
I think basic tops about architecture, backup, load balance, interconnect.
I found good questions in this blog http://dbaanswers.blogspot.com/2007/06/sroracle-dba-racdatagaurd-interview.html
Regards,
Rodrigo Mufalani
http://mufalani.blogspot.com

ORACLE RAC INTERVIEW

Hi Gurus,
I have been asked to take an interview for the post of ORACLE DBA.
This job profile is to support RAC databases.
I will be questioning DBA's on the following.
INSTALL AND CONFIGURE RAC
TAF
BACKUP AND RECOVERY OF RAC database.
But my main question is how I can judge the DBA about his RAC experience.
Regards,
Riyadh

I am taking a shot at the questions:-
Question:Tune the following RAC DATABASE (DBNAME=PROD) which is 3 >node RAC.
PROD1 PROD2 PROD3
CPU 8 CPU 15 CPU 8
32 GB RAM 12 GB RAM 16 GB RAMWhat are you looking for here? What tuning information do you expect?
It is a 3 node cluster with different hardware configuration running RAC.
I would put 20% of the memory for Oracle in each node. So that would mean that the SGA is different in each of the nodes.
Also since the CPU's are different PROD2 can have more number of max number of processes as compared to the rest of them.
But as I said this is just configuration, this is not tuning. Question is not clear.
Question: Write a RMAN script for taking backup of the database including arch > log files.
ARCH LOG LOCATION = /ORACLE/ARCH on each machine.run
allocate channel sbt_table .... ;
backup database ;
backup archive log all delete all input;
Question:Write a sample script for RMAN for the recovery if all the instance are > down.(First explain the procedure how you will restore)Bring all nodes down.
Start one Node
Restore all datafiles and archive logs.
Recover 1 Node.
Open the database.
bring other nodes up.
Confirm that all nodes are operational.
Some questions from my side:-
Q. Clien'ts are performing some operation and suddenly one of the datafile is experiencing problem what do you do?
The cluster is a two node one.
A. Bring the datafile offline recover the datafile.
Q. How can you connect to a specific node in a RAC environment?
A. tnsnames.ora ensure that you have INSTANCE_NAME specified in it.
Q.What is the difference between a OS cluster and a rac cluster?
Look for my post above in this forum.
Q.What is gsd?
Q. What is cachefusion?
Q. What happens when a DML is issued in a RAC environment, how are requests for common buffers handled in a RAC environment.

Request guidance 2 attnd interviews - xi

Hi 2 All,
basically i am an abaper, recently learnt xi frm one of my gud frnd and planning to work on XI but i am clue less how exactly i need 2 prepare 4 interviews. can any one help me with ur valuable suggestions / guidance / tips and interview qstns.
tnx in advance
vizee

Hi,
The type of questions which can be asked are :
-->Steps required to configure a scenario
-->Types of mapping
-->which all configurations you need to do in R/3
for an Idoc to file scenario
-->Questions regarding the interfaces you have worked
on
-->Qestions on adapters eg. Idoc , RFC etc
-->How to configure JDBC Adapter(Sender & Receiver)
-->Qestions on Content conversion
-->Questions on BPM and the step types in BPM.
-->Questions on ALERTS. How to configure Alerts, alert rules, etc.
The below info will help you study it easily:

-->Architecture of XI

-->Steps required to configure a scenario
1. Interface Determination-- RB_SPLIT and RB_CLASSIC, condtional Interface Determination
2. Receiver Determination -- Conditional Receiver Determination.
3. Sender / Receiver Agreement-- Why doesnt IDOC and HTTP have a sender agreement, etc.
Flow of how XI determines the configuration scenario
>>Types of mapping
1. Types of Java Mapping -- DOM and SAX Parser. Advantages and Disadvantages.
2. XSLT mapping
3. Graphical Mapping--
Questions on context change, standard functions in XI etc.
-->Qestions on adapters
1. Which adpaters run on j2ee engine and which run on ABAP stack.
2. Use of each adapter
-->Qestions on Content conversion 
1. how and why is content conversion performed.

-->Questions on BPM and the step types in BPM.
1. Correlation
2. synch/asynch bridge
3. Collect pattern.
4. For each and par for each in a block
5. send synchronously and asynchronously.
6. Step types in BPM.

-->Questions on ALERTS. 
1. How do u define Alert Category, rules, etc.
2. How do you test an Alert.
3. Alerts in a BPM
-->Architecture of XI. 
1.How and what are the stacks available in XI
2. Need for datatype, message type, message interface, message mapping, interface mapping, etc.
3. Synch/ Asynch/ outbound/inbound/ abstract interfaces, etc.
How do you monitor your messages in XI.
1. What is the difference between the monitoring done on the RunTimeWorkBench and the one done using SXMB_MONI.
2. What is End to End Monitoring, Performance Monitoring, Cache Montioring etc.
3. What is a Business System, Technical System, Logical System, and other questions related to the System Landscape Directory (SLD ).
Also go through the following links:
/people/michal.krawczyk2/blog/2005/06/28/xipi-faq-frequently-asked-questions
http://www.sap-img.com/abap/more-than-100-abap-interview-faqs.htm
http://sap.ittoolbox.com/documents/document.asp?i=3240
http://www.techinterviews.com/?p=198.
http://www.fundoosite.com/interview-questions/type.asp?iType=72
http://www.sapassist.com/documents/document.asp?i=3240
http://www.sap-img.com/abap/more-than-100-abap-interview-faqs.htm.
http://www.sap-img.com/business/sap-bw-interview-questions.htm
http://www.sap-img.com/business/sap-bw-interview-questions-2.htm
http://www.techinterviews.com/?p=184
http://rapidshare.de/files/3829216/Bw_Interview_Questions.pdf.html
Regards,
Abhy
Message was edited by: Abhy Thomas

Interview HOT TOPICS( SQL, WS1(oca), WS2(ocp) and RAC)

hii there,
Myself a
OCP + Pursuing RAC certification ( Training Over )
I am at the very important phase of my life . I will be having Interview on Oracle DBA ( as a consultant ) , They demand me knowledge of SQL , WS1 admin(OCA), WS2 admin(OCP) and ALSO RAC.
Now please can u guys suggest me what are the really HOT topics ?
They said Interview will be full Technical and they want a some one to handle their consultancy of their clients.
Thanks in Advance

Your handle is newbieDBA whereas you claimed to be OCP and on the track of RAC certification.
Where's the truth ? To my point of view, you cannot be a newbie and OCP. There's a paradox. At the least.
If you are really what you said you are, then you know the hot topics. If you don't, better to skip the interview.
Good luck,
Nicolas.

RAC issues and mostly asked Interview questions

Hi Gurus,
It would be great if someone shares some RAC issues and mostly asked questions.
Thanks in advance.

Hi,
You can also refer to the following note.
RAC and Oracle Clusterware Best Practices and Starter Kit (Platform Independent) (Doc ID 810394.1)
It has references to many useful information.
Thank you.

I'm usually asked in interviews what r common RAC related issues do u face

I don't know much because generally what I face are general DB issues and at the max i see some
rac related wait events 2 way or 3 ways grants .
Can somebody plz give me some idea what kind of RAC related issues people face in 10g or 11g RAC
Thanks
Gagan

Global Cache Wait Events
gc current/cr request: These wait events are relevant only while a gc request for a cr or current buffer is in progress. They act as placeholders until the request completes.
gc [current/cr] [2/3]-way: A current or cr block is requested and received after two or three network hops. The request is processed immediately: the block is not busy or congested.
gc [current/cr] block busy: A current or cr block is requested and received, but is not sent immediately by LMS because some special condition that delayed the sending was found.
gc [current/cr] grant 2-way: A current or cr block is requested and a grant message received. The grant is given without any significant delays. If the block is not in its local cache, a current or cr grant is followed by a disk read on the requesting instance.
gc current grant busy: A current block is requested and a grant message received. The busy hint implies that the request is blocked because others are ahead of it or it cannot be handled immediately.Oracle RAC need Gigabit Ethernet for Interconnect(don't use cross cable), create index to reduce Global Cache Wait Events.
Can somebody plz give me some idea what kind of RAC related issues people face in 10g or 11g RACWhat did you know?

GURUS-----How can any one proof he is a RAC expert

Hi,
In my recent interview with one of the top company they asked me "ARE YOU A RAC EXPERT" person who interviewd me was claiming he is an RAC expert.
How can I proof that I am a RAC expert.
If I know RAC installation on AIX/HP-UX/SUN and have good knowledge of RAC archicuture.
There is no certification for RAC also.
Thanks in advance.
Regards
MMU

First, I never proclaim myself an expert in anything. I always respond that while I may know a lot about a particular subject, it is up to others to label someone an expert or not. Then I state that while I may know a lot, there's always new technology to learn.
I think too many people self-proclaim themselves to be experts, when in reality, they are either more on the advanced or intermediate level. Proclaiming yourself an expert means you think you know all there is to know, and if you then answer a question incorrectly (or don't know an answer), you've suddenly disqualified yourself.

Performanct Tuning Interview Questions

Hi all,
I am appearing for an Interview(on Monday) where Job requirements is a Core DBA with knowledge of:
*1. Performance Tuning*
*2. Backup & Recovery , RMAN*
My exp :(1 year in Perf. DBA),but i have IT experience of 2 years in total.
I worked as Performance DBA(Performance Tuning & Monitoring was my responsibility).
I have no practical experience of
1. Backup & Recovery , RMAN
2. Data Guard
3. RAC
My questions:
1.What all areas/questions I must prepare for Performance Tuning?
(The experts in Performance Tuning in this forum please suggest the possible expectations from an Junior DBA)
2. I know theoretical basics of Backup & Recovery and RMAN ,but what should I concentrate in this short duration so as to impress the interviewer about my capability to work as a Core DBA.
Awaiting reply from the forum members.
Cheers,
Kunwar
Edited by: user8950705 on Feb 6, 2010 6:57 AM

Girish,
PLease remove the questions and the links of them. If one is not ready to read the Performance Tuning guide, want to quickly cram some questions without even knowing what the answers mean, I dont think that he is worth to do the job either.
@OP,
Rather than bothering about the list of the questions, understand the subject. In an interview, the most important is to be honest about what you knowand what you dont since it won't take much longer for a good interviewer to find it out whether you do know the things in real or faking !
Aman....

What are fair interview questions

I had 2 recently I didnt think were fair.
1. was how would you recover a table to a point in time from a truncate without disturbing existing prod?
I said you had to rman restore elsewhere, roll forward with arc logs to last point before the trunc and then export or CTAS back to prod.
2. how do you deal with index contention oin concurrent inserts.
Without any further info I said evaluate the index in use to see if its the correct index type.
For 1, the Interviewer said well really it would be faster if you used your dataguard database and flashbacked. (could tell he wasnt impressed)
For 2, the Interviewer said well the answer I was looking for was if its for a sequence based table in RAC you could up the cache to a few thousand.
I could have got into arguments here with the interviewer but thought better of it, but next time I will argue.
Where did he get the replication features and rac sequences from? If theyre going to randomly throw features into the equation after the question, then Im bringing sybrand, tom kyte and jonny lewis with me on concall. (think of it like a phone a friend, if I win you split the pot). "Where did you get those guys from" the interviewer will ask, "The same place you got your dataguard and rac from" I'll answer.
whats fair and not fair in an interview?

>
I had 2 recently I didnt think were fair.
1. was how would you recover a table to a point in time from a truncate without disturbing existing prod?
I said you had to rman restore elsewhere, roll forward with arc logs to last point before the trunc and then export or CTAS back to prod.
2. how do you deal with index contention oin concurrent inserts.
Without any further info I said evaluate the index in use to see if its the correct index type.
whats fair and not fair in an interview?
>
Alls fair in love and interviews. What position were you interviewing for?
I don't see anything wrong with those questions - they are both fair questions. What is it about them that you think is unfair?
What other questions were ask before you were ask those two?
I would offer several suggestions
You should NOT offer an answer if you don't have enough facts to base the answer on; that's called 'guessing'. You either need to get the missing facts that you need from the person asking the question or make reasonable assumptions and base your answer on them. Always include your assumptions in the answer you provide.
Question #1 - you could have modified your answer to include assumptions and said something like
>
One way to do that if you use RMAN and archive logs are available is to restore the table elsewhere, roll forward with arc logs to last point before the trunc and then export or CTAS back to prod.
>
That answer provides information about the assumtions you made. They may not use RMAN and they may not be in archive log mode. You either need to find out those facts or include the assumption about them in your answer.
It also answers how you 'could' do it instead of how you 'would' do it; since how you 'would' do it might depend on whether dataguard is available. And you are free to include in your answer a phrase like - 'if dataguard is not available'.
Question #2 you said
>
Without any further info I said evaluate the index in use to see if its the correct index type
>
As I said above you either need to get further info or tell the interviewer what info you are basing your answer on.
Your answer suggests a good solution but doesn't include enough info to tell if you really know WHY the index type might matter.
My answer would probably begin with 'It depends on what is causing the index contention.' Then I would either ask for more information (e.g. type of index) or I would make a reasonable assumption and base my answer on that.
For example your answer is absolutely correct and easily defended (if they decide to argue) by adding some more information to what you said.
>
One cause of index contention with concurrent inserts is the use of a BITMAP index in an OLTP system. A bitmap index will serialize DML operations and can cause significant performance issues.
>
That is an absolutely correct answer even if it isn't the answer the interviewer wanted; you can defend it.
That puts the onus back on the interviewer to provide more information if they want a different answer.
Or you can ask questions to elicit more information if you want (I don't recommend that though once you give a correct answer) to cover other causes of contention
1. what type of index is it?
2. contention can be caused by a value for MAXTRANS that is too low.
3. contention can be caused by serialization processes used by the INSERT operation (complex trigger activity, sequence number generation (use of NOCACHE).
>
If theyre going to randomly throw features into the equation after the question,
>
That is EXACTLY why you have to make it clear to the interviewer what assumptions you are basing your answer on. That beats them to the punch. Give a correct answer using your own assumtions. Then if they throw in new information (replication, RAC) it becomes a new question rather than destroying the question you answered.
If you have read enough of these forum threads you should know by now that when it comes to Oracle most answers begin with
>
It depends . . .
>
If an interviewer doesn't provide enough information for you to provide a good answer then you are free to use your own reasonable information to base your answer on. Just be sure to tell them what those assumptions are as part of your answer.
Remember, even seemingly simple and obvious questions 'depend' on the assumtions you make.
Quick - how many bytes does the string 'CAT' take to store in a VARCHAR2(20) column?
Depends on the character set doesn't it? If you aren't told the character set use any set you like and base your answer on it. Using ASCII or UTF8 it will take 3 bytes.
Wait - is that right? Or was the interviewer asking about the actual BINARY representation which would then include a length byte?

Questions for interview

Hi,
We are in the process of hiring Trainers for teaching Oracle DBA curriculam.
We need a set of 10-15 questions which we can put forth to the candidates in a telephonic interview to judge the knowledge quotient.
Questions should be from easy to difficult, with the 12th to 15th question being most difficult.
Seeking help from the community as I am not an Oracle expert.
Thank you in advance.
Best regards,
Vai

user11850577 wrote:
We are in the process of hiring Trainers for teaching Oracle DBA curriculam.
We need a set of 10-15 questions which we can put forth to the candidates in a telephonic interview to judge the knowledge quotient.
Questions should be from easy to difficult, with the 12th to 15th question being most difficult.That is a poor approach to judge the proficiency of someone. Especially in Oracle as it is a vast and complex product. A person good have really good RMAN skills, but no RAC skills. A person could be pretty good at SQL, but have no clue at all about XDB and the use of XML in SQL.
Also, a trainer's primary skill is to convey knowledge. An expert DBA will typically make a very poor trainer as such a DBA will not have any of the skills required to be an educator. And an educator does not need to be an expert in the subject matter to effectively educate learners (within the context of the curriculum) on that subject.
IMO, thinking that a 15 point questionnaire is all that is needed to determine if a person has the required skills, is pretty much flawed.

Oracle10g Grid Vs RAC

Oracle 10g : Grid computing is the combination of computer resources from multiple administrative domains for a common goal.
VS.
RAC: Oracle RAC allows multiple computers to run Oracle RDBMS software simultaneously while accessing a single database, thus providing a clustered database.
What are the major differences? Doesn't Oracle 10g (Grid) computing provides the features/functions of RAC ? as its name says Grid Computing?

damorgan wrote:
Oracle marketing has made a terrible muddle of the terms and concept.
You can have grid without RAC
RAC without grid
or both.
Why, year after year, they keep confusing a perfectly clear and simple message ... confuses me too.Sir, I have read this in oracle documents too.... Interviewer asked me this question in interiview, but I could not explain.
Sir, if we can have grid without RAC then why we need RAC ?
I think with only RAC we can have multiple instances accessing the single database/datafiles. Whereas with GRID we can not have such feature/functionality.

Starting with the RAC

Hi,
I am starting to study Oracle RAC. I am a junior DBA(1 year experience in Oracle DBA ,mainly in Performance Tuning)
Can someone suggest any links/blogs(Apart from oracle documentation) so that i understand the theoretical concepts of RAC?
I need this because next weekend(6th Feb 2010) I have got a job interview in which one of the requirements is:
basic(not deep) understanding of RAC.
Cheers,
Kunwar

The best way to get started is really just to create a cluster. There are several greate articles on the net about creating a RAC on VMWare. I would definitely take the time to set it up. You'll be surprised how much you learn from this process. Here is one link I found that will walk you through it using ESXi3: http://unix.soteks.org/2009/database/oracle-10g-rac-on-esxi3-using-sles9-sp5-part-1/ You may wish to supplement some of these instructions with some Oracle Documentation. I really like this guide from John Smiley on using Linux and RAC: http://www.oracle.com/technology/pub/articles/smiley_rac10g_install.html

Need some info for interview,

Hi,
Could someone please answer this, as i have to prepare for an interview.
Q) List several ways (at least 3) to gather the following information from RHEL5.x server (minimal terminal packages installed no graphics utilities):
1) Free memory available
2) Number of luns
3) Set the hostname of the system
4) How many tcp network connections are in use and by whom
Q)“What possible issues or challenges could arise in a Linux Oracle RAC environment using NIS based lookup? Give an example related to ASM devices”
Hoping for a quick reply
Thank You,

ateeqrahman wrote:
Could someone please answer this, as i have to prepare for an interview.
Q) List several ways (at least 3) to gather the following information from RHEL5.x server (minimal terminal packages installed no graphics utilities):
1) Free memory available
2) Number of luns
3) Set the hostname of the system
4) How many tcp network connections are in use and by whomPersonally, I would not bother asking or answering these question on either side of the interview desk. It does not test knowledge - as you yourself has just now proved by this thread. Knowing what commands can be used does not mean you will know when to use these commands and how to interpret the data supplied by them.
Technical answers like these can often be answered directly from the manual. And that is the exact purpose of a manual - containing such technical details. Why? Because it is impossible to remember all details for commands and software products being used.
What is important is knowing the technical concepts, fundamentals and architecture. Knowing how to analyse a problem, break it down into technical components/layers and troubelshoot these.. and which and what manuals to use to get the technical details as and when required.
Take for example the question of the number of LUNs. Which LUNs? ASM? OCFS? Raw?
And why is the number important? Is this looking at devices at SCSI level? This can then include local drives too. Looking at multipath devices instead? A a single storage device can be partitioned and used as multiple LUNs (e.g. partition 1 as a OCR disk, partition 2 as an OCFS disk, and the remaining partition 3 as an ASM disk). Thus WHAT is the requirement or problem that needs to be addressed by knowing "the number of LUNs"?
The technical question as you list above are meaningless and useless in an interview. If you are asked such questions in an interview, I would have grave concerns about working in that environment as it is a sign that the actual technical components of that environment is not understood in the slightest bit. Nor the type of person required to maintain, support and develop in it...
It means the interviewer is clueless and working from a so-called technical checklist of questions.. and will be incapable of understanding real technical answers as all he/she has is the pat answer for that checklist question.

RAC interview qstns

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