Gurkulindia.com celebrating it’s first anniversary

Ramdev

I have started unixadminschool.com ( aka gurkulindia.com) in 2009 as my own personal reference blog, and later sometime i have realized that my leanings might be helpful for other unixadmins if I manage my knowledge-base in more user friendly format. And the result is today's' unixadminschool.com. You can connect me at - https://www.linkedin.com/in/unixadminschool/

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71 Responses

  1. Naresh says:

    Congrats gurkulindia.com

  2. Subba says:

    All the best ra Ramu. do well. 

  3. Congrats & All the very best Ramdev. Wish you a great journey ahead.

  4. Rajesh Devabhaktuni says:

               
                                 All the best Ramdev.  

    hats off to you on your patience to write these long articles and share even after long working hours.  I hope you are doing good there ….!

    Thanks.  Keep Doing …. :)

  5. Eldho says:

    Hi Ramdev, Hearty Congratulations to you.
    Really appreciate your support towards the SA community.
    Wishing all the very best for the future endeavors of Gurukulindia.com

  6. srikanth says:

    Congrats and thanks for giving Valuable info reg Solaris

  7. seema says:

    Congratulation Ramdev …

  8. Michael says:

    Congrtulations Ramdev ….. Keep Posting 

  9. Ali says:

    Congrats , hope it flourish more and more and you get blessed with lot of success. thanks again.

  10. teesamlovesu says:

    wish you all the best Gurukal india…

  11. Yogesh Raheja says:

    Thanks a lot @teesamlovesu for your wishes!!..

  12. Anand says:

    Congratulations on this amazing feat. I wish all the very best and lot more growth !!

  13. ramakrishna says:

    this is very good site for SA.KEEP going on 100 years.thanks alot for a directorsssssssss

    keep watching GURUKULINDIA.

  14. Yogesh Raheja says:

    @Ramakrishna, thanks a lot for your boosters and we will try our level best to keep our services provided for many more years to go!!..:) Thanks again!!..

  15. ramakrishnA says:

    hi ram i need one help for you.

    1)
    Need to run hardware diagnostics on server 2)what is the difference between one server has a faulty disk which need to be replaced.&&&& Need to be replace the faulty DIMM. PLS resolve the issue.
    thanks, ramakrishna

    • Ramdev says:

      @ ramakrishna:

      >>>> 1)Need to run hardware diagnostics on server
      System admins/ support engineers run hardware diagnosis on Sun machines by booting from a diagnosis CD/DVD. And this require a complete server downtime from 2 to 4 hours depending on the server model. And what ever regular diagnosis we run using explorer ( or other commands ) are called os level diagnosis.
      >>> 2)what is the difference between one server has a faulty disk which need to be replaced.&&&& Need to be replace the faulty DIMM. PLS resolve the issue.
      This question seems to be an interview question rather than a troubleshooting question. And the guy who asked you this question might be expecting you to know the Sysadmin tasks while replacing a faulty Disk and Faulty DIMM ( Memory modules).

      ****** In general for the DIMM ( memory replacement) system admins dont do any tasks at OS level, they will simply shutdown the server and then opens the case and replaces the memory. And normally System admins wont physically open the server, they will just shutdown the server but the sun support engineer will replace the memory.
      ———————————————————————————
      ******* For the faulty disk replacement, system admin has to perform some tasks before replacing the disks. And they are .
      1. If the disks are configured with our any redundancy ( e.g. mirroring or raid5) you should take the backup of entire data from the disk before you replace.
      2. If the disks were configured with redundancy, just make sure you have detached the faulty disks from redundant mirror or raid 5 volumes.
      3. you have to check whether the faulty disk hot swappable ( means : disk can be removed and inserted back while the server powered on) or does it require down time.
      4. make sure disk is not in use by user / process while replacing it.
      5. Then go ahead for disk replacement.
      6. once disk replaced you have to rebuild the raid mirror ( if exists earlier). If the disks had no mirror/raid5 setup you have to format, partition, create filesystem, mount filesystem and then restore the data from the backup to new disk.

  16. Ameer says:

    Really  good job Ramdev!!!

    All the best for your effort.

  17. ramakrishnA says:

    hi ramdev, please resolve it.

  18. Yogesh Raheja says:

    @ramakrishnA, which OS you are using. Let me know I will try to provide you with the procedure.

  19. ramakrishna says:

    hi yogesh,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,solaris os.this is troubleshooting issue.could you please provide the provide.we need solaris9 and 10 procedures.

  20. ramakrishna says:

    hi ramdev……………………………………………….thankyou for giving suggition.thanks alot

  21. vaibhav pansare says:

    Congrats to Gurkul … I hope more admin will join and share their thoughts and updates here …I found the contents are very useful .

  22. Yogesh Raheja says:

    @Vaibhav, thank you very much and welcome to gurkul.

  23. Santhosh Kumar Reddy says:

    Congrats Ramdev and gurkulindia 

  24. Rinold says:

    Congrats gurkulindia.com.All the best for the future.

  25. Ramdev says:

    @Rinold – Thanks for the wishes and support, we are successfully completing our second year very soon :).

  26. ramakrishna says:

    Hi Team

    one doubt

    1. how can i increase the MAX concurrent sftp/ssh connection from DEFAULT to 100 on eqgnvclusuat1.us.db.com

    2. how can i add healthy threshold time to disconnect idle ssh/sftp cl——-solaris 5.10

    pls solve

    • Ramdev says:

      @ramakrishan –

      for question1 – as per man sshd_config , MaxSessions parameter sets for concurrent open sessions.
      for question2 – to configure timeout from the server side, you have to set three parameters from the sshd_config file ClientAliveCountMax, ClientAliveInterval and TCPKeepAlive. And again man sshd_config is your best friend for more detailed information about these settings.

  27. Sankar says:

    Congrats Ramdev, keep your great work ….

  28. Chandra sekhar says:

    @Sekhar
    Hi ram,Congrats, keep your great work
    One doubt: how to know disk space availability in svm at the time of increase file system(df -h will give file system free space and used space) how to the volume free space in svm..

    • Ramdev says:

      Sekhar, i don’t remember any direct commands for this. All you have to do is, run the format to check the partition table for the free space, and then create new slice with the available free space. Later you have to initialize and use the new slice for any kind of SVM operations.

  29. ramakrishna says:

    HI Ram,

    what is the use of below commads,…………..
    # bootadm update-archive -R /a
    Creating boot_archive for /a
    updating /a/platform/sun4u/boot_archive

    i got above commands in failsafe mode. PLS EXPLAIN RAM,,,

    • Ramdev says:

      hi ramakrishna, the simple bootadm update-archive command updates the boot-archive in the root filesystem i.e. “/”
      When we boot into failsafe mood we mount the root filesystem on top of mount-point “/a”, to update the boot-archive for the alternative root “/a” we use the option “-R /a” ( -R option is for alternative root.)

  30. Ramakrishna says:

    Thank you very much RAMDEV……..

  31. Chandra sekhar says:

    Thank u ram

  32. Chandra sekhar says:

    hi ram, one doubt once deleted any directory using cmd rm -rf, is there any alternative way to restore that dir(not from backup team)

  33. Chandra sekhar says:

    hi ram, i am updating veritas cluster and zones if u have any document please send my mail id, some issues with explanation regarding cluster,
    Thanks and regards
    Sekhar
    chandrasekhar.e16@gmail.com

  34. Sir ,
    What is network roots
     what is the command to see how many hard disk are connected to the server.
    what is difference between the hpblades and dell poweredge servers
    .Pls provide the answers

    Thanks & Regards:
    Mahesh babu.R

  35. Maheshbabu says:

    pls provide some information about the itil process in linux. it urgent

    • Ramdev says:

      Mahesh, ITIL is about overall IT Infrastructure management and it is not related to any operating system or technology. All it talks about

      >>Incindent management : How to interact and coordinate with various support teams when there is an alert comes from any IT infrastructure
      >>Problem Management : How to deal with the recurring alerts , and how to find the permanent solutions for repeating incidents
      >> Change Management : What are the rules and procedures to be followed to introduce a change in current working production infrastructure.
      >>Knowledge Management : How to maintain the documentation about IT infrastructure
      >>Configuration Management : How to keep track of each and individual component of IT Infrastructure e.g. server, network switch , storage …etc

  36. Maheshbabu says:

    thanks for you reply. I would request you to provide some more  informationsir.please do needful for me.

  37. Maheshbabu says:

    Sir ,
    What is network roots
     what is the command to see how many hard disk are connected to the server.
    what is difference between the hpblades and dell poweredge servers
    .Pls provide the answers

    • Ramdev says:

      Hi Mahesh, just a question, are you new learner or already working ? The reason, I am asking is, your questions are very random in nature.

      if you are learning things from the scratch. I would like to refer some good links which you must read and understand as a learner.

  38. Maheshbabu says:

    Sir, Pls provide what is arp in dhcp. what is its use.

  39. Maheshbabu says:

    Sir,
        I am searching for linux adminstration job . When i went fujitsu comapny they asked these type of questions. Thats why iam posting the questions which  i wasnot  able to answer the questions. Please do needful for me by providing the answers.

  40. Ramdev says:

    Mahesh,

    Q >> What is network route ???
    Ans >> Network Routing is the process of moving a packet of data from one network to another network based on the destination IP address.we will have one entry for each network path, which called as network route.

    e.g :  
    Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
    192.168.33.0    0.0.0.0         255.255.255.0   U         0 0          0 bond0

    Q >>  what is the command to see how many hard disk are connected to the server.
    Ans >> in linux,  ise fdisk -l    

    Q>>> what is difference between the hpblades and dell poweredge servers
    Ans >> i am not sure what difference the interviewer experiencing from you, may be it was a question to test about your understanding about individual servers and blade servers.
    dell edge are like individual servers, you can rack them independently  ( refer http://www.dell.com/sg/business/p/poweredge-c6145/pd) . Where as HP blade servers are something like small modules that you insert in a common chassis (it is similar to just imagine a bookshelf with multiple books  each chassis will hold around 8 to 16 modules — reer http://bladesmadesimple.com/wp-content/uploads/2010/03/c7000w16.jpg. ) and you manage all of them using centrailzed management console called ILOM.

    Q>>> what is the purpose of ARP?

    A>> When systems connected in the network, we know that systems will  communicate with each other using 3 different information 1. Hostname 2. IP address 3. Ethernet MAC addresses. ( A unique code assigned to each network interface card in your server e.g :  AE:AC:DE:23:32:44).

    At the lower level, systems always have to use the MAC address to send or receive packets. But we no where use MAC address in our configuration in our commands or configuration.

    Example: if you want to connect to a server you either use “ssh  myserver” or “ssh 192.169.101.12” , but you never use like “ssh 43:ad:43:44:cd:ad” right?
    But system needs to know the MAC address of the server, before it start the SSH. to find the MAC address related to the specific server or IP, it will use ARP protocol.

    In simple words ( or interview words) the asnwer is  ” ARP is used to map the MAC addresses to IP addresses” 

  41. Mahesh babu.R says:

    Thanks for your answers. How to see the virtual servers runing in our machine.
    2.how to see the network cards in our system .
    3.what is the command current running  service port numbers.
    4.how the kernel compliation and pacthing the server happens.

    Your answers are helping me alot. thank u once again sir.

  42. Mahesh babu.R says:

    Also. What is  Event Viewer in server & check blacklists

  43. Maheshbabu says:

    sir, what is performance bottlenecks?

  44. Maheshbabu says:

    Thanks for your answers. How to see the virtual servers runing in our machine.
    2.how to see the network cards in our system .
    3.what is the command current running  service port numbers.
    4.how the kernel compliation and pacthing the server happens.
    Your answers are helping me alot. thank u once again sir.

  45. Maheshbabu says:

    HI SIR,

    What is the difference between software Raid  & Hardware Raid.
    what is the satellite server patching.
    If the server is in usa  and the server is crashed no one is there to contact. how to resolve the issue.
    If volume group is full and how to add the logical volume with out using the extra partition.
    what is gfs. how it is used.
    these questions are asked in tcs. where it didnot answer properly. pls provide thw answers. 
     

  46. Ramdev says:

    Mahesh,  Please try to read and understand the below provided posts to get your answers for your questions.  I don’t want to  misdirect you by giving direct answers because the questions may not be same in the next  interviews.
        I want you to gain solid knowledge in the areas where most of the interviewers will focus.
        If you have difficulty with any specific area during interview , just let me know so that i can advice you  the way to  improve that parts.

    ### how to see the network cards in our system .

    >> refer http://gurkulindia.com/main/2012/06/linux-network-troubleshooting/#more-3223

    ### what is the command current running  service port numbers.

    >> refer http://gurkulindia.com/main/2012/11/redhat-enterprise-linux-networking-troubleshooting-quick-reference/

    ### how the kernel compliation and pacthing the server happens.

    >> http://gurkulindia.com/main/2012/11/redhat-linux-kernel-faq-and-quick-reference/

    ### What is the difference between software Raid  & Hardware Raid.

    hardware raid is something that we setup from system bios level, and operating system don’ need any configuration for that. Software raid something we do from linux level, by using the volume manager tools like mkraid , lvm or vxvm.

    refer >>> http://gurkulindia.com/main/2011/11/linux-identify-if-linux-was-installed-in-a-hardware-raid/

    ### If the server is in usa  and the server is crashed no one is there to contact. how to resolve the issue.

    >>> refer :   http://gurkulindia.com/main/2011/10/day-in-sa-life-working-remotely-for-an-hardware-issue/

    ### If volume group is full and how to add the logical volume with out using the extra partition.

    >> refer http://gurkulindia.com/main/2011/08/experience-lvm-logical-volume-manager-with-real-time-examples/
    >> refer http://gurkulindia.com/main/2012/11/redhat-linux-lvm-troubleshooting-reference/

  47. Maheshbabu says:

    Thanks for your answers and it is good for me going through the concepts.where compare to the direct answers

  48. Mahesh babu.R says:

    Hi sir, Introubleshooting part i am having doubt

  49. Mahesh babu.R says:

    Sir,

    How to install linux servers on hp blade server.

    pls forward some link for learner

  50. Mahesh babu.R says:

    pls  refer some good links for learner.

  51. Mahesh babu.R says:

    Also , what is recrussion in DNS sir. Asked in interview in wipro infotech.

  52. Mahesh babu.R says:

    Hi,

    When ever network interface goes up or down we need the write the network control scripts .who will prepare that scripts whether it is possible to run by the sys admin.
    sorry for the individual questions. Pls provide the answers 

  53. Ramdev says:

    Hi Mahesh, I love to answer all of your questions, but this post is not a right place to discuss about interview questions.  Please join the  group https://www.facebook.com/groups/Just.unix.no.noise/ , where we have many helpful folks who can quickly help you for your questions. If you any specific question related to any post posted here, please feel to ask it here so that my answers will be useful for other readers.

  54. Srinivas says:

    Hi Ramdev

    What us meant by setuid and setgid in solaris and when it can be applied on a file.

    • Ramdev says:

      Hi Srinivas, If you have a script called test.sh, which internally has some commands which can only be run by your account.

      Just incase if you want to give the execution permission to everyone on this script you normally do 755 so that others will have execution permission. but the problem here is , you gave execution permission only to the script test.sh but not to the internal commands, that makes internal commands fails to run for the other users.

      Just to avoid this problem, we can specify the system to run the script with your account ( by SUID) and group (by SGID) identity even though they were executed by others, so that the internal commands won’t complain the permission issues.

      catch here is we do set SUID or SGID to executable files alone, for other files or directories it has no affect.

  55. Prajwala says:

    Thanks Ramdev

  56. Chandra Sekhar says:

    Hi Ram,

    how can up the interface(net0) card up in solaris 11 it showing status down (#dladm show-phys)

    • Ramdev says:

      Hi Sekhar, if the device down and it the dladm show-links also sayings same then you might need to check the network interface connectivity and duplect settings both from switch and server side.

  57. Deepak says:

    Congrats Ram

  58. saran says:

    Hi Ram,

    Please provide some basic documents for ITIL process followed in real time environmnent

  59. maheshbabu.r says:

    HI RAM,
    We are having the activity of Decommission of Solaris server with zones,zfs file system ,vxvm fs. Can Any one help mwe with the steps of decommission.

  60. ramakrishna says:

    greate work ramdev,thanks for your greate support on Gurukul india for System Admins future site.everyone is waiting for your articles.THANKS FOR YOUR HARD WORK.Welcome to Home town(India) (now its Rajahmundry (AP) is become as SA Hub)

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