Printable View
Hello..,
I am developing an application using VB as front end and Oracle8i as backend..I am not able to do the Backup and restore part..How can i take the Oracle Database backup?It's urgent..could anybody help me please..
Thanks in advance,
Poornima.
The preference is always to use RMAN for online backups whereever possible. However, if you can afford the down time, just shut the database down and copy all the datafiles\controlfiles\archivelogs to some other storage device.
as an application developer maybe you will prefer to do an export of the database and if you need to restorer the data you can do import after that.
You use imp and exp utilities, or the expdp and impdp in Oracle 10g.
they arent backup methods, very bad adviceQuote:
as an application developer maybe you will prefer to do an export of the database and if you need to restorer the data you can do import after that.
You use imp and exp utilities, or the expdp and impdp in Oracle 10g.
Davey,
I think you should be a bit clearer, you make it sound like waitecj's post is also bad advice. When I'm guessing you're just talking about oracli's.
for a developer database a import/export is a good backup method. You can separately import tables as needed. It provides convinience. You can make separate exports on separte tables/schemas after some changes in the application and can import only those if needed. If you need a image copy of the database the best is to do a backup using Recover Manager (rman).Quote:
Originally Posted by davey23uk
as i said, an export is not a backup method and its bad advice, you will lose data with it - doesnt matter if he is a developer a dba, a cleaner or the CEO's love child a backup needs to be a proper one
Oracli,
cheery_poori asked how to do a backup. Exp/imp is not a backup method, I'm not saying it doesn't have it's uses, but it isn't a valid backup method. Rather than arguing with Davey follow this http://asktom.oracle.com/pls/ask/f?p...D:832427034486
and search for
'do not even remotely consider use EXP as a "backup" tool'
I think you can guess who said it from the link.
I know it is not a proper "backup" for a production database, I recommended it to cheery_poori as he is obviously not experienced with the Oracle database as a DBA, and the database he is using is for development, so if he uses a rman ora pure copy of datafiles/redos/controlfiles he might make a mistake and not be able to restore/recover the database at all (knowing many developers treat the DB as a black box). I still say exp/imp is a better solution for this situation.
The things are nto always black and white. If cheery_poori sais he needs a backup maybe someone should first asked him what kind of backup does he like and from what situation to be able to recover, what options does he have for backuing up does he even have a separete storage where he would do a backup or he will use a tape so he will need a media manager for RMAN.
Sometimes there are "custimzed" solutions to problems.
AN EXPORT IS NOT A BACKUP!!! get it? never has and never will be, it is a tool for moving data between databases
if you use export, you will lose data - any solution that means you lose data is by definition not a backup!!!!
Sooner everyone realises that the sooner people like him stop coming back saying i've lost my data, can i recover from an export without losing data
if it is a tool just for moving data you say you lose data when you move them from one db to another?!? :) You did not understood me what I meant in the situation ... whatever...
what davey was saying is that you will lose data if you use exp as a backup tool, not when moving data from one db to another.
I think he did undertstand you perfectly. If you create an export and then 3 days later suffer catastrophic media failure you will lose anything done to the db from the point of the export onwards - DATA LOSS. DATA LOSS = invalid backup (in my opinion).
If you're happy with that then that's your call but don't go advising it to people asking for help, at least not without confirming that they're happy with the risk involved.
anyway, I'm quickly losing the will to live....
But it is the same with a a cold backup not being in archivelog mode as advised by waitecj in the beginning, nobody asked if the database is in archivelog mode. Do you not lose data in such a case if your DB is not in archivelog mode and you just make a cold backup over night and have a catastrophy during the day. (And don't just copy phrases from Tom Kythe)
I will say it again RMAN is the best backup method, but as an addition or in some cases it is good to exp/imp. What happens for example if somebody updates some table by mistake (the whole table) or drops some vital procedure you cannot easily recreate and you just have a cold backup and noarchivelog and you don't have enough space to make a copy of the DB from the cold backup and you don't want to lose other tables? How do you restore that just one table (the DB is v 8.1.7 so there is not flashback table :-) Ina development DB this can be a more usual case of catastrophy than losing a disk.
So backup strategy is not as simple as just tell to people make a copy of your datafiles/controlfile and redos. Or just say use RMAN - you must devise a backup strategy for a certain scenario.
So nobody gave an suffucinatly well descritpion of how to make an Oracle backup WITHOUT losing data for each scenario that might happen. In situations like this it is best to read the documentation not rely just on short tips from a forum.
I explicitly stated that he backup archivelogs if he is shutting down the database to perform an OS backup. Therefore it is pretty reasonable to assume that I had implicitly stated "this guy is in archivelog mode". If he isn't, then i'd hope he would come back and say he isn't, then we might be able to help him further.Quote:
Originally Posted by oracli
we will post phrases from Tom Kyte as he knows what he is talking about and is a valid source of knowledge
And yes a noarchivelog mode backup is just as useless, but that wasnt the point of the discussion. Exports were
the point was a backup for different situations from which you can acyually restore your data.Quote:
Originally Posted by davey23uk
Nice perspective on the whole issue. Maybe we should just have saved all the arguments and given the original guy that link! ... next time.