Oracle RAC Interview Questions & Answers


1. Where are the Clusterware files stored on a RAC environment?
The Clusterware is installed on each node (on an Oracle Home) and on the shared disks (the voting disks and the CSR file)
2. Where are the database software files stored on a RAC environment?
The base software is installed on each node of the cluster and the
database storage on the shared disks.
3. What kind of storage we can use for the shared Clusterware files?
- OCFS (Release 1 or 2)
- raw devices
- third party cluster file system such as GPFS or Veritas
4. What kind of storage we can use for the RAC database storage?
- OCFS (Release 1 or 2)
- ASM
- raw devices
- third party cluster file system such as GPFS or Veritas
5. What is a CFS?
A cluster File System (CFS) is a file system that may be accessed (read and write) by all members in a cluster at the same time. This implies that all members of a cluster have the same view.
6. What is an OCFS2?
The OCFS2 is the Oracle (version 2) Cluster File System which can be used for the Oracle Real Application Cluster.
7. Which files can be placed on an Oracle Cluster File System?
- Oracle Software installation (Windows only)
- Oracle files (controlfiles, datafiles, redologs, files described by the bfile datatype)
- Shared configuration files (spfile)
- OCR and voting disk
- Files created by Oracle during runtime
Note: There are some platform specific limitations.
8. Do you know another Cluster Vendor?
HP Tru64 Unix, Veritas, Microsoft
9. How is possible to install a RAC if we don’t have a CFS?
This is possible by using a raw device.
10. What is a raw device?
A raw device is a disk drive that does not yet have a file system set up. Raw devices are used for Real Application Clusters since they enable the sharing of disks.
11. What is a raw partition?
A raw partition is a portion of a physical disk that is accessed at the lowest possible level. A raw partition is created when an extended partition is created and logical partitions are assigned to it without any formatting. Once formatting is complete, it is called cooked partition.
12. When to use CFS over raw?
A CFS offers:
- Simpler management
- Use of Oracle Managed Files with RAC
- Single Oracle Software installation
- Autoextend enabled on Oracle datafiles
- Uniform accessibility to archive logs in case of physical node failure
- With Oracle_Home on CFS, when you apply Oracle patches CFS guarantees that the updated Oracle_Home is visible to all nodes in the cluster.
Note: This option is very dependent on the availability of a CFS on your platform.
13. When to use raw over CFS?
- Always when CFS is not available or not supported by Oracle.
- The performance is very, very important: Raw devices offer best performance without any intermediate layer between Oracle and the disk.
Note: Autoextend fails on raw devices if the space is exhausted. However the space could be added online if needed.
14. What CRS is?
Oracle RAC 10g Release 1 introduced Oracle Cluster Ready Services (CRS), a platform-independent set of system services for cluster environments. In Release 2, Oracle has renamed this product to Oracle Clusterware.
15. What is VIP IP used for?
It returns a dead connection IMMIDIATELY, when its primary node fails. Without using VIP IP, the clients have to wait around 10 minutes to receive ORA-3113: “end of file on communications channel”. However, using Transparent Application Failover (TAF) could avoid ORA-3113.
16. Why we need to have configured SSH or RSH on the RAC nodes?
SSH (Secure Shell,10g+) or RSH (Remote Shell, 9i+) allows “oracle” UNIX account connecting to another RAC node and copy/ run commands as the local “oracle” UNIX account.
17. Is the SSH, RSH needed for normal RAC operations?
No. SSH or RSH are needed only for RAC, patch set installation and clustered database creation.
18. Do we have to have Oracle RDBMS on all nodes?
Each node of a cluster that is being used for a clustered database will typically have the RDBMS and RAC software loaded on it, but not actual data files (these need to be available via shared disk).
19. What are the restrictions on the SID with a RAC database? Is it limited to 5 characters?
The SID prefix in 10g Release 1 and prior versions was restricted to five characters by install/ config tools so that an ORACLE_SID of up to max of 5+3=8 characters can be supported in a RAC environment. The SID prefix is relaxed up to 8 characters in 10g Release 2, see bug 4024251 for more information.
20. Does Real Application Clusters support heterogeneous platforms?
The Real Application Clusters do not support heterogeneous platforms in the same cluster.

21. Are there any issues for the interconnect when sharing the same switch as the public network by using VLAN to separate the network?

RAC and Clusterware deployment best practices suggests that the interconnect (private connection) be deployed on a stand-alone, physically separate, dedicated switch. On big network the connections could be instable.
22. What is the Load Balancing Advisory?
To assist in the balancing of application workload across designated resources, Oracle Database 10g Release 2 provides the Load Balancing Advisory. This Advisory monitors the current workload activity across the cluster and for each instance where a service is active; it provides a percentage value of how much of the total workload should be sent to this instance as well as service quality flag.
23. How many nodes are supported in a RAC Database?
With 10g Release 2, we support 100 nodes in a cluster using Oracle Clusterware, and 100 instances in a RAC database. Currently DBCA has a bug where it will not go beyond 63 instances. There is also a documentation bug for the max-instances parameter. With 10g Release 1 the Maximum is 63.

24. What is the Cluster Verification Utiltiy (cluvfy)?
The Cluster Verification Utility (CVU) is a validation tool that you can use to check all the important components that need to be verified at different stages of deployment in a RAC environment.
25. What versions of the database can I use the cluster verification utility (cluvfy) with?
The cluster verification utility is release with Oracle Database 10g Release 2 but can also be used with Oracle Database 10g Release 1.
26. If I am using Vendor Clusterware such as Veritas, IBM, Sun or HP, do I still need Oracle Clusterware to run Oracle RAC 10g?
Yes. When certified, you can use Vendor Clusterware however you must still install and use Oracle Clusterware for RAC. Best Practice is to leave Oracle Clusterware to manage RAC. For details see Metalink Note 332257.1 and for Veritas SFRAC see 397460.1.
27. Is RAC on VMWare supported?
Yes.
28. What is hangcheck timer used for ? 
The hangcheck timer checks regularly the health of the system. If the system hangs or stop the node will be restarted automatically.
There are 2 key parameters for this module:
-> hangcheck-tick: this parameter defines the period of time between checks of system health. The default value is 60 seconds; Oracle recommends setting it to 30seconds.
-> hangcheck-margin: this defines the maximum hang delay that should be tolerated before hangcheck-timer resets the RAC node.
29. Is the hangcheck timer still needed with Oracle RAC 10g?
Yes.
30. What files can I put on Linux OCFS2?
For optimal performance, you should only put the following files on Linux OCFS2:
- Datafiles
- Control Files
- Redo Logs
- Archive Logs
- Shared Configuration File (OCR)
- Voting File
- SPFILE
31. Is it possible to use ASM for the OCR and voting disk?
No, the OCR and voting disk must be on raw or CFS (cluster file system).
32. Can I change the name of my cluster after I have created it when I am using Oracle Clusterware?
No, you must properly uninstall Oracle Clusterware and then re-install.
33. What the O2CB is?
The O2CB is the OCFS2 cluster stack. OCFS2 includes some services. These services must be started before using OCFS2 (mount/ format the file systems).
34. What the OCR file is used for? 
OCR is a file that manages the cluster and RAC configuration.
35. What the Voting Disk file is used for? 
The voting disk is nothing but a file that contains and manages information of all the node memberships.
36. What is the recommended method to make backups of a RAC environment?                          RMAN to make backups of the database, dd to backup your voting disk and hard copies of the OCR file.
37.  What command would you use to check the availability of the RAC system?
crs_stat -t -v (-t -v are optional)
38. What is the minimum number of instances you need to have in order to create a RAC?
You can create a RAC with just one server.
39.  Name two specific RAC background processes
RAC processes are: LMON, LMDx, LMSn, LKCx and DIAG.
40.  Can you have many database versions in the same RAC?
Yes, but Clusterware version must be greater than the greater database version.
41.  What was RAC previous name before it was called RAC?OPS: Oracle Parallel Server
42.  What RAC component is used for communication between instances?Private Interconnect.
43.  What is the difference between normal views and RAC views?A RAC view has the prefix ‘G’. For example, GV$SESSION instead of V$SESSION
44.  Which command will we use to manage (stop, start) RAC services in command-line mode?
srvctl
45.  How many alert logs exist in a RAC environment?
A- One for each instance.
46. What are Oracle Clusterware Components
Voting Disk — Oracle RAC uses the voting disk to manage cluster membership by way of a health check and arbitrates cluster ownership among the instances in case of network failures. The voting disk must reside on shared disk.
Oracle Cluster Registry (OCR) — Maintains cluster configuration information as well as configuration information about any cluster database within the cluster. The OCR must reside on shared disk that is accessible by all of the nodes in your cluster
47. How do you backup voting disk
#dd if=voting_disk_name of=backup_file_name
48. How do I identify the voting disk location
#crsctl query css votedisk
49. How do I identify the OCR file location
check /var/opt/oracle/ocr.loc or /etc/ocr.loc ( depends upon platform)
or
#ocrcheck
50. What is SCAN?
Single Client Access Name (SCAN) is s a new Oracle Real Application Clusters (RAC) 11g Release 2 feature that provides a single name for clients to access an Oracle Database running in a cluster. The benefit is clients using SCAN do not need to change if you add or remove nodes in the cluster.

100 comments:

  1. why voting disk is always in odd numbers ?

    ReplyDelete
    Replies
    1. selected disks in storage area from node r greater than 50% of disks in storage area.(if we have 2 disks in storage area, u select one==>50%of disks(1) this is equal to 50% not greater than 50% so,we mAINTAIN ODD NO. OF DISKS IN STORAGE AREA(STANDARD STORAGE)

      Delete
  2. Because every node ping voting disk as they are alive in cluster and connected with each other via private network (interconnect). When this interconnect is not working properly then at that time nodes are try to ping voting disk whether they are alive. Which nodes ping most voting disk it is the part of cluster and rest is evicted from cluster, and cluster is saved from multiple brain syndrome. If voting disk are in even count then both nodes are survival node and it is craeted multiple brain in same cluster. If the voting disks are in odd number then in that case only one node ping greater count of voting disk and we save our cluster from "Multiple Brain Syndrome"

    ReplyDelete
  3. Oracle Real Application Cluster [10g/11 g R2 RAC]
    www.21cssindia.com/courses_view.html?id=1‎
    Oracle-Application Online Training, Oracle-Application training, Oracle-Application course contents, Oracle-Application , call us: +919000444287 ...

    ReplyDelete
  4. Thanks for sharing this interesting and useful blog..

    Oracle Training in Chennai

    ReplyDelete
  5. Comfortably, the article is in reality the greatest on this noteworthy topic. I concur with your conclusions and will thirstily look forward to your upcoming updates about orace rac training in chennai

    ReplyDelete
  6. Really i am luck to found this site. Thanks for sharing valuable informations.

    Oracle Training in Chennai

    ReplyDelete
  7. Nice blog ,
    You have provide a lovely information this will helpful to us very much keep posting Oracle RAC DBA Online Training

    ReplyDelete
  8. I get a lot of great information from this blog. Recently I did oracle certification course at a leading academy. If you are looking for best Oracle Training in Chennai visit FITA IT training and placement academy which offer SQL Training in Chennai.

    ReplyDelete
  9. There are lots of information about latest technology and how to get trained in them, like Big Data Training in Chennai have spread around the web, but this is a unique one according to me. The strategy you have updated here will make me to get trained in future technologies(Big Data Training). By the way you are running a great blog. Thanks for sharing this. cloud computing training chennai

    ReplyDelete
  10. Basic questions . Good for beginners

    ReplyDelete
  11. Oracle DBA Training in Chennai
    Thanks for sharing this informative blog. I did Oracle DBA Certification in Greens Technology at Adyar. This is really useful for me to make a bright career..

    ReplyDelete
  12. Whatever we gathered information from the blogs, we should implement that in practically then only we can understand that exact thing clearly, but it’s no need to do it, because you have explained the concepts very well. It was crystal clear, keep sharing..
    Websphere Training in Chennai

    ReplyDelete
  13. Data warehousing Training in Chennai
    I am reading your post from the beginning, it was so interesting to read & I feel thanks to you for posting such a good blog, keep updates regularly..

    ReplyDelete
  14. Selenium Training in Chennai
    Wonderful blog.. Thanks for sharing informative blog.. its very useful to me..

    ReplyDelete
  15. Oracle Training in chennai
    Thanks for sharing such a great information..Its really nice and informative..

    ReplyDelete
  16. SAP Training in Chennai
    This post is really nice and informative. The explanation given is really comprehensive and informative..

    ReplyDelete
  17. This information is impressive..I am inspired with your post writing style & how continuously you describe this topic. After reading your post,thanks
    for taking the time to discuss this, I feel happy about it and I love learning more about this topic..
    Android Training In Chennai In Chennai

    ReplyDelete
  18. Pretty article! I found some useful information in your blog, it was awesome to read,thanks for sharing this great content to my vision, keep sharing..
    Unix Training In Chennai

    ReplyDelete
  19. I found some useful information in your blog, it was awesome to read, thanks for sharing this great content to my vision, keep sharing..
    SalesForce Training in Chennai

    ReplyDelete
  20. There are lots of information about latest technology and how to get trained in them, like Best Hadoop Training In Chennai in Chennai have spread around the web, but this is a unique one according to me. The strategy you have updated here will make me to get trained in future technologies Hadoop Training in Chennai By the way you are running a great blog. Thanks for sharing this blogs..

    ReplyDelete
  21. This is really an awesome article. Thank you for sharing this.It is worth reading for everyone. Visit us:
    Oracle Training in Chennai

    ReplyDelete
  22. very nice blogs!!! i have to learning for lot of information for this sites...Sharing for wonderful information.Thanks for sharing this valuable information to our vision. You have posted a trust worthy blog keep sharing.Oracle DBA Training in Chennai

    ReplyDelete
  23. great article!!!!!This is very importent information for us.I like all content and information.I have read it.You know more about this please visit again.
    Oracle RAC Training in Chennai

    ReplyDelete
  24. Wonderful tips, very helpful well explained. Your post is definitely incredible. I will refer this to my friend.SalesForce Training in Chennai

    ReplyDelete
  25. I am reading your post from the beginning, it was so interesting to read & I feel thanks to you for posting such a good blog, keep updates regularly.
    Java Training in Chennai

    ReplyDelete
  26. Really awesome blog. Your blog is really useful for me. Thanks for sharing this informative blog. Keep update your blog.
    PHP Training in Chennai

    ReplyDelete
  27. Thanks for sharing this valuable information to our vision. You have posted a trust worthy blog keep sharing.Nice article i was really impressed by seeing this article, it was very interesting and it is very useful for me..
    Android Training in Chennai

    ReplyDelete
  28. Really awesome blog. Your blog is really useful for me. Thanks for sharing this informative blog. Keep update your blog.
    SAP Training in Chennai

    ReplyDelete
  29. Excellent information with unique content and it is very useful to know about the information based on blogs.
    Hadoop Training in Chennai

    ReplyDelete
  30. Tks very much for your post.

    Avoid surprises — interviews need preparation. Some questions come up time and time again — usually about you, your experience and the job itself. We've gathered together the most common questions so you can get your preparation off to a flying start.

    You also find all interview questions at link at the end of this post.

    Source: Download Ebook: Ultimate Guide To Job Interview Questions Answers:

    Best rgs

    ReplyDelete
  31. This information is impressive; I am inspired with your post writing style & how continuously you describe this topic. After reading your post, thanks for taking the time to discuss this, I feel happy about it and I love learning more about this topic..
    Informatica Training in chennai | QTP Training in Chennai




    ReplyDelete
  32. new horizon security services manassas va I am really impressed with your efforts and really pleased to visit this post.

    ReplyDelete
  33. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com. Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  34. Hi Dear,
    your providing such a valuabe information about studying..and also have some good key points to every student.
    ORACLE ADF

    ReplyDelete
  35. Very nice post. Find More Interview Tips For freshers here - Visit Here

    ReplyDelete
  36. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com. Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  37. Good Post! Thank you so much for sharing this pretty post, it was so good to read and useful to improve my knowledge as updated one, keep blogging…
    Regards,
    Oracle DBA Training in Chennai|Oracle apps Training in Chennai|Oracle Training

    ReplyDelete
  38. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com. Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  39. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com. Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  40. hai this is jessica,this article is awesome it is very useful to me and our company.ithubonlinetraining

    ReplyDelete
  41. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com. Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  42. KnowledgeCert is a pioneer in providing the professional certification course like ITIL Intermediate Planning,Protection & Optimization in US & would like to present to you our upcoming ITIL Intermediate Course Boot Camp in US.Take advantage of World Class Training!

    ReplyDelete
  43. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  44. PLease send me latest 12c New features in RAC and RDBMS to my mail - mallikarjjun@gmail.com

    ReplyDelete
  45. Bed Bug Exterminator Maryland It is really a great and useful piece of information. I am glad that you shared this helpful info with us. Please keep us up to date like this. Thank you for sharing.

    ReplyDelete
  46. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  47. Really awesome blog. Your blog is really useful for me.
    Thanks for sharing this informative blog. Keep update your blog.
    Oracle Training In Chennai

    ReplyDelete
  48. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  49. this article nice ,this information is very useful to me and our company OracleRACOnlineTraining

    ReplyDelete
  50. Best Java Training Institute In ChennaiThis information is impressive; I am inspired with your post writing style & how continuously you describe this topic. After reading your post, thanks for taking the time to discuss this, I feel happy about it and I love learning more about this topic..

    ReplyDelete
  51. dumpster rental annandale Galaxy Transfer is based in Northern Virginia and is a division of EnviroSolutions, Inc. GT was purchased by EnviroSolutions, Inc. in June 2013.

    ReplyDelete
  52. Thanks for sharing these information. It’s a very nice topic. We are providing online training classesOracleRACOnlineTraining

    ReplyDelete
  53. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  54. Thanks for sharing these information. It’s a very nice topic. We are providing online training classesoracleraconlinetraining

    ReplyDelete
  55. Thanks for sharing these information. It’s a very nice topic. We are providing online training classesoracleraconlinetraining

    ReplyDelete
  56. Thanks for sharing these information. It’s a very nice topic. We are providing online training classesoracleraconlinetraining

    ReplyDelete
  57. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  58. Thanks for sharing these information. It’s a very nice topic. We are providing online training classesoracleraconlinetraining

    ReplyDelete
  59. Thanks for sharing these information !!!! Your Fashion Hub

    ReplyDelete
  60. useful information... thank you.

    ReplyDelete
  61. Paris airport transfer - Parisairportransfer is very common in Paris that provides facilities to both the businessmen and the tourists. We provide airport transfers from London to any airport in London and also cruise transfer services at very affordable price to our valuable clients.

    Paris taxi
    Paris airport shuttle
    paris hotel transfer
    paris airport transfer
    paris shuttle
    paris car service
    paris airport service
    disneyland paris transfer
    paris airport transportation
    beauvais airport transfer
    taxi beauvais airport
    taxi cdg airport
    taxi orly airport

    ReplyDelete
  62. Florida Personal Injury Attorney Very interesting topic will bookmark your site to check if you write more about in the future.

    ReplyDelete
  63. Great information and presented in useful manner

    We have lot of good oracle stuff here

    ReplyDelete


  64. I like your suggestions they are really helpful. Thank you so much for sharing this post.

    Hadoop Certification in Chennai

    ReplyDelete
  65. Thanks for the Q and A, It's awesome and I loved reading it. Useful stuff. I found one more good resource related to Oracle DBA Interview Questions and answers which will give an updated collection of to Oracle DBA Interview Q and A.

    ReplyDelete
  66. Yours guidence on Oracle RAC is helpful to learners. Thanks for providing the needed information on Oracle RAC online training

    ReplyDelete
  67. Great Post !!!! Your question and answer on the Oracle RAC will be useful for candidates attending Database interviews. Thanks for sharing, keep sharing. But I had found one better and effective E-learning website related to Database. database is an organized collection of data.[1] It is the collection of schemas, tables, queries, reports, views and other objects. More Info: Database

    ReplyDelete
  68. virginia landfills Established in 2003, EnviroSolutions is a vertically integrated solid waste collection, disposal and recycling company located in the Northeast and Mid-Atlantic regions of the United States.

    ReplyDelete
  69. Your design of the blog is really eye-catching. More over the content is also very productive. Information you have provided is really very beneficial.UNIX training in noida

    ReplyDelete
  70. I am really impressed along with your writing skills and also with the format on your blog. Visit: Online Mock Interview Practice

    ReplyDelete
  71. This is what I was looking for from last week. Great work done. :)
    I like the way you write. Awesome, keep it up.
    Wow!!! Honestly speaking you are really a great writer. What I required I got it. Thank you so much.
    ORACLE training

    ReplyDelete
  72. Thank you for making this site very interesting! Keep going! You're doing very well
    online interview guide

    ReplyDelete
  73. Very nice and useful question and answers thank you for sharing this info. Know more about Oracle DBA Training In Bangalore

    ReplyDelete
  74. Wow, what a fantastic post. The best post around. Thumbs up
    free online interview preparation

    ReplyDelete
  75. Rolex Watches Authentic Mens & Ladies Rolex Datejust, President Watches for Sale at JavyEstrella.com.

    ReplyDelete
  76. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  77. For latest and updated certification dumps (for Oracle/Cisco/Microsoft/ITIL/RedHat/Salesforce/Cloudera/many more..) in PDF format contact us at completeexamcollection@gmail.com.
    Refer our blog for more details http://completeexamcollection.blogspot.in/

    ReplyDelete
  78. paris airport service - We provides, taxi chauffeur or airport shuttle services, taxis services in paris, hotel in very reasonable price between Paris and Paris Airport for more call us at +33 (0) 157 425 801.

    Address: Paris VIP Limo ltd,
    Phone: +33 (0) 157425801
    Post code: 75008, 75116, 75016,
    Email: resa@parisviplimo.com
    Website: http://www.parisairportransfer.com/

    ReplyDelete

  79. great article , Your post is very informative and helpful for us to improve my knowledge and skills.

    Amazon Web Services Training In Hyderabad

    ReplyDelete
  80. great article , Your post is very informative and helpful for us to improve my knowledge and skills.
    oracle training in chennai

    ReplyDelete

Note: Only a member of this blog may post a comment.