Backups in Oracle

[lynn814]

Hi!!

I am just new to the Backup scene in Oracle. I have been put in charge of coming up with a proper backup strategy for my company. I would like info on the following point:

1> what should i consider when creating a backup strategy?
2> is it better to conduct backups using ARCHIVELOG mode or through RMAN. Can we use both?
3> is it possible in Oracle to have the backup sent directly to a tape drive or will they have to be copied manually from disk?
4> how does Oracle do incremental backups?

Thanks a lot for all ur help

Regards
Lynn

[sudip]

1) First of all judge the availability of yr Database i.e. whether it is 24x7 database. Also find out how much downtime can yr management take.
2) RMAN can take backups of databases both in Archivelogmode and non archivelog mode. Using RMAN you can forget about what was backed up and when. It stores everything in the control file or in a separate repository in a different datbase.
3) RMAN is capable of directly copying files onto the tape.
4) RMAN is able to do incremental backups. If using exports you can take incremental backups.

[dknight]

Here are some other things to consider:

You should list the different types of failure and the steps used to remedy each.

For example, node failure will be different than disk failure, and different than user failure.

To use RMAN effectively, you should set it up on a different node than your primary database. In addition, there is substantial advantage to creating a recovery catalog when using RMAN.

On 8.1.5, there is an interface to Legato Storage Manager that allows easy operation of an automated tape device.


Hope that helps.

[sreddy]

Your backup strategy pretty much goes with how much down time your database can afford to have from day to day problems, apart from disaster recovery which has to be looked at different angle.

[m_d_marian]

Question:

When doing online backups with RMAN, the database must also be on ARCHIVELOG mode, rigth?

[lynn814]

thanks guys.

We have an 8.1.5 database on an NT Server. It is a 24x7 system, but updates occur only till 2 pm since those are our timings. The size of our database is about 25GB.

We plan to take a complete backup first & thereafter do incremental backups.
So should I go in for RMAN only? Or should I do the first full backup using the OS commands and use RMAN for the incremental backups? Is that possible?

Thanks
Lynn

[rwpayne]

Here's my 2 cents...
1. How much data? This is critical because in many cases it will limit your backup options. In addition, you need to know if the data is largely static or dynamic. Obviously, the more dynamic your data the greater the need for frequent backups.

2. I always recommend running in archivelog mode. This also allows you to perform hotbackups; that is backup the db without interruption of service. Performance may degrade a bit but the db will still be available for use. Logical backups or exports are always an option. However, you lose the ability to perform point-in-time recovery. They require less time to complete as well as a smaller amount of disk space. Again, no interruption of service. Cold backups require service interruption and are very disk/tape space intensive. This is usually used for large dbs that cannot be backed up via hot or export in a timely manner.

3. Yes, backup directly to tape is possible. However, you should do both disk and tape until you've successfully proven your ability to restore from tape.

4. Via RMAN; there is some overhead in backing up using RMAN.



[QUOTE][i]Originally posted by lynn814 [/i]
[B]Hi!!

I am just new to the Backup scene in Oracle. I have been put in charge of coming up with a proper backup strategy for my company. I would like info on the following point:

1> what should i consider when creating a backup strategy?
2> is it better to conduct backups using ARCHIVELOG mode or through RMAN. Can we use both?
3> is it possible in Oracle to have the backup sent directly to a tape drive or will they have to be copied manually from disk?
4> how does Oracle do incremental backups?

Thanks a lot for all ur help

Regards
Lynn [/B][/QUOTE]

[rwpayne]

On-line infers archivelog mode. Without the db being in archivelog mode you could not recover the db up to a specific point in time.


[QUOTE][i]Originally posted by m_d_marian [/i]
[B]Question:

When doing online backups with RMAN, the database must also be on ARCHIVELOG mode, rigth? [/B][/QUOTE]

[rwpayne]

Yes, I recommend a weekly hot backup (db stays on-line) and RMAN incrementals.


[QUOTE][i]Originally posted by lynn814 [/i]
[B]thanks guys.

We have an 8.1.5 database on an NT Server. It is a 24x7 system, but updates occur only till 2 pm since those are our timings. The size of our database is about 25GB.

We plan to take a complete backup first & thereafter do incremental backups.
So should I go in for RMAN only? Or should I do the first full backup using the OS commands and use RMAN for the incremental backups? Is that possible?

Thanks
Lynn [/B][/QUOTE]