BACKUP/RECOVERY

I have this question, it sound not too wise but I want to prove it to someone it's not right. Any way, I took over this client and I asked them how they run their back up. The answer I got from them is they backup the whole server every Sunday, and incremental every night. Is that right to do ??? I thought we have to backup the database to somewhere say a disk on different location and then backup that disk.

Please let me know it's right to backup the whole server. What is the advantage& disadvantage of backing up the whole server ??? What is the consequence when we try to recover ??? Please give me as much senerios as possible.

thanks

If they are doing an OS backup, then No, it is probably not correct. The tablespaces must be put in backup mode in order to be backed up.

An incremental OS backup is worthless in an oracle environment since the data files change every checkpoint anyway.

There are 2 main types of backup.

Named ON-LINE or OFF-LINE.

OFF-LINE backups are simple and provide limited recovery, you can only recover up to point of your last backup. If they are backing up the server whilst the database is shutdown this is ok.

ON-LINE backups are so called because they are performed whilst the database is open. If your company is 'backing up' the whole server whislt the database is open then this back up is useless as your datafiles will not be consistent. An actual on-line backup procedure is needed where you place each tablespace into backup mode individually and copy the files.

INCREMENTALS are database exports, only of the data that hasd changed since the last incremental export.

The correct type of backup must be decided and implemented.

For me I backup the database off-line every weekend and take a full export daily. I could then restore the datafiles and import the latest data I have if necessary.

If your company are not shutting down oracle whilst they back up there server then they have no usable backups.

That form of backup is useful for me as I have a very simple database :).

If an on-line backup is needed then your database must be in archive log mode and your company must be storing these logs as somewhere as well as the datafile copies they make.

ooooooo it's fun :)

Thanks for all of your reply. I do understand the concept, that's right I think it's wrong.

I need some strong arguement so I can prove it wrong.

simple, OS incremental backup is useless so basically your customer has one cold backup set per week, if database crashes he is gonna lose probably one week work, data bye bye

the best way to prove a backup/recovery method is to actually attempt to recover a database using your backups. Simple as that.

Get a test environment going and try to use their OS/Incremental (BS) method. You will show that it will not work and you look great in their eyes.

enjoy!
- Magnus