Backup method

[sansan]

Hi, All:

We have a new system installed Oracle 8.1.6. Now we are considering the method of Backup/Recovery.

In our system 2 disks and 1 tape device can be used for backup. And I think there are 2 ways to use them:
1). 1 disk : archive log;
1 disk : backup using by RMAN;
1 tape : backup's backup
2). 1 disk : archive log;
1 disk : the copy of the archive log;
1 tape : backup using by RMAN;
I don't know which is better? which is common?(The data size is about 20GB)
Can some one give me some advices?

Thanks.

[marist89]

This all depends on how the disk is layed out. Is disk#1 mirrored? If not, option #1 would be out IMHO because your archived redo logs do not have any redundancy. If disk#1 is mirrored, option #1 would yield the best performance.

[sansan]

Thanks for your help.

Would you tell me what IMHO means?

Disk#1 is not mirrored, so we don't have the second archived redo log. Do you mean that the mirror of the Disk#1 is most important? Should I increase another DISK?