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Thread: How to ask questions in a forum!! Newbees and exp. people pay attention!

  1. #11
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    Originally posted by sreddy
    I don't think that kinda clients/corporates exist in this internet era who can wait for couple of hours to bring their database back on line with import and no indexes and creating indexes again might take some time again.
    Yea they do exists, and hence my comments. One of my application fits into this category. Also remember, not all applications are still upto speed with internet. It is different story that one need not need Oracle for that kind of application. Like I said before, many time you have to just do what you are told to by your manager.
    -- Dilip

  2. #12
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    Originally posted by patel_dil
    Like I said before, many time you have to just do what you are told to by your manager.
    I'm missing something here how does it matter to application what kinda B&R methodology you use for database. If I'm managing the database, I'm responsible for data on database not my manager. I will take the best solution for B&R not what manager wants cuz, he is favorite of Exp/Imp. Unless they do not want to give me hard disk to save my backup files (In that case I will not be having disk for exp dumps either).

    This is not for the sake of argument but, for the sake of dba who needs take best measures for safe guarding the data on the database he is responsible for.
    Last edited by sreddy; 05-21-2003 at 02:33 PM.
    Reddy,Sam

  3. #13
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    Originally posted by sreddy
    I'm missing something here how does it matter to application what kinda B&R methodology you use for database. If I'm managing the database, I'm responsible for data on database not my manager. I will take the best solution for B&R not what manager wants cuz, he is favorite of Exp/Imp. Unless they do not want to give me hard disk to save my backup files (In that case I will not be having disk for exp dumps either).

    This is not for the sake of argument but, for the sake of dba who needs take best measures for safe guarding the data on the database he is responsible for.
    I wish it was that easy!

    In my company (300,000+) the application is responsible for letting us know what is acceptable. some of the less critical apps can afford to loose 24 hours worth of data, so a daily export is fine for them. No need for Archive mode either.

    Budget, licensces, certification and DASD come into play as well.
    You have to have the proper liscence in place.
    The app needs to be approved by upper management (tested, payed for, ect....
    You need to plan ahead for the proper DASD and that costs money.
    The impact your B&R methodology will have on the application. I know when we implemented archive log on one app, they called us screaming with performance problems.

    So, around here you have to go through all the proper channels, you can't simply do what you want. Multiple departments have to get involved, and that has it's good and bad points.

    MH
    I remember when this place was cool.

  4. #14
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    the problem withj export import is not that you can lose 24 hour or 48 hours data whateever

    the problem is you need to recreate a new database, import is slow as hell, can your company afford 5 ~6 hours downtime (for a small database)? our development database ranges from 10gb to 100gb, if I had to restore the 50gb+ ones how long it would take? probably one whole day, with backup takes one hour or less or more but not a whole day that's for sure

    if you can afford that downtime so then go ahead and do your export/import
    Last edited by pando; 05-21-2003 at 02:56 PM.

  5. #15
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    Mr. Hanky,

    Yeah! I understand now. But if you think over from B&R perspective Is'nt its lot easier to have daily hot backup midnight which takes away costs on disk for archive logs. DBAs can recover within 15 to 30 minutes rather few hours to import and recreate indices and go from there.

    Thats whole another story of enabling archive mode and issues with performance which can be tuned for optimum performance. I don't see benifits having only exp/imp B&R methodology. I see only the practical benefit off of exp/imp methodology is object level recovery (Human mistakes of table drops etc.) Anyway, it has become more likedebate now
    Reddy,Sam

  6. #16
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    I only said that (about export/import) to curry favor with Jeff. But it really is a good topic for discussion.

  7. #17
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    Originally posted by pando
    the problem withj export import is not that you can lose 24 hour or 48 hours data whateever

    the problem is you need to recreate a new database, import is slow as hell, can your company afford 5 ~6 hours downtime (for a small database)? our development database ranges from 10gb to 100gb, if I had to restore the 50gb+ ones how long it would take? probably one whole day, with backup takes one hour or less or more but not a whole day that's for sure

    if you can afford that downtime so then go ahead and do your export/import
    But again in a large company this is all agreed to.

    Most of the time you are recovering one table.
    Never since I have been here have we had complete failure on a system. Not that that is any kind of reason for using imp/exp.
    Usually with the larger DB's the recovery time is taken into account before a B&R methodology is decided upon.

    MH
    I remember when this place was cool.

  8. #18
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    Originally posted by sreddy
    Mr. Hanky,

    Yeah! I understand now. But if you think over from B&R perspective Is'nt its lot easier to have daily hot backup midnight which takes away costs on disk for archive logs. DBAs can recover within 15 to 30 minutes rather few hours to import and recreate indices and go from there.

    It's a good idea to have ANY backups run after hours to avoid impacting the business,
    I remember when this place was cool.

  9. #19
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    Originally posted by sreddy
    Mr. Hanky,

    Thats whole another story of enabling archive mode and issues with performance which can be tuned for optimum performance. I don't see benifits having only exp/imp B&R methodology. I see only the practical benefit off of exp/imp methodology is object level recovery (Human mistakes of table drops etc.) Anyway, it has become more likedebate now
    HA! Not in an NT envioronment with limited resources and disk space. One batch job and you come in to a hung database. It quickly became a maintenence nightmare. Again, the apps group and another group (that handles the instance) decided on this and it was implemented. I was the one that insisted on removing it.

    I really do not want to get into a imp/exp B&R debate because it is a moot point. We all know it is not the best B&R methodology, BUT in the real world it does exist. I inherited it, and as I said it is for less critical apps. I don't think we could afford to have everyone of our apps running in archive log mode with multiple backups, ect...

    MH
    I remember when this place was cool.

  10. #20
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    The application I am talking is about 10 GB in size, small enough that application users are able to do a restore in under 1 hour. Export is done daily by application users, Import(say Restore) only done occasionaly. Mind you, I said this is done by Application users, who have no idea what export or import is. They only think they are taking backups. DBA's are called when all "efforts" by application users fails to get data restored.

    Sam, I would never talk about "responsibilities" with managers, especially the ones who think they KNOW(be it technical or otherwise) more than any DBA's or Developers do Not when they give you written specs that export/import is the way to do it.

    My point is not about export/import the right Backup/Restore tool. It is about situation where you are forced to use it.
    -- Dilip

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