Re: Backup strategy

sds_at_dataplusnet.com (Strategic Data Systems) wrote:
>I have followup question on the use of 'hot backups'.
>
>I am running Oracle 7.0.x on an IBM RS/6000 under AIX.
>If the put my tablespace in backup mode, and then proceed to backup the
>datafiles using my favorite UNIX backup utilitiy, do I get a 'good' backup
>of the datafile since there still is activity on the data file(s)?
>
>It would seem I would not, since I am backing up an ever changing file.
>
>==================================================================
>Scott Overby sds_at_dataplusnet.com
>SDS
>Sheyboygan, WI 53082
>==================================================================
If you're running the database in ARCHIVELOG mode you will, because Oracle records in it's controlfiles that a backup is in progress and all changes are still protected by writing them to the redologfiles. The minor disadvantage is of course, when the database crashes during backup you will probably have to go back to your last cold (off-line) backup and recover from there. By the way, running in ARCHIVELOG mode enables you to repair nearly all kinds of errors, except for user errors of course (accidentally dropping a table, deleting records and so on). To prevent this you still have to make exports on a regular basis, as the redolog files contain transactions only. If you don't have an export, simply go back to your last cold backup, do a manual recovery just before the table was dropped, export the table, restore the backup again and do a complete recovery. This might be very troublesome, however..

Sybrand Bakker
Senior I.S. Analyst
Bentley Systems Europe

All my views are my own Received on Thu Jun 08 1995 - 00:00:00 CEST