Ref:(Few queries on Hot Backup)

[atkinson]

Hi,

I have few queries on Hotbackup which are as follows:

1. Will it make any difference in performance of Hotbackup , if the the hotbackup is taken by putting all the tablespace in 'Backup' mode or putting tablespaces in Backup' mode by one by one.

2. Will it make any difference in performance of tablespace backup , if the one of the script is performing DML operations on the objects in the tablespace while it is being backedup?.

3. Are there any difficulties in recoveries , if the hotbackup is taken at a time for all tablespaces in one go , one by one tablespace?. If there are difficulties , which way is best?

Please give reply for my above queries , as our hotbackup is taking lot of time to get finished.


Cheers,

[marist89]

What's your bottleneck? Are you backing up to disk or tape? Can your backup medium handle more I/O?

[atkinson]

Hi,

We are taking backup directly to the tapes, our backup media can handle more I/O , which is unlikely.

Cheers,

[slimdave]

Best practice is to put TS's in backup mode only while they are being backed up, especially if DML ops are being performed.

The reason for this is that on the first occasion that a block is modified on a TS in hot backup mode, Oracle writes some additional redo information. To reduce this overhead you want to minimize the amount of time (and thus the potential number of blocks modified) for which TS's are in backup mode.

[manodba]

3. Are there any difficulties in recoveries , if the hotbackup is taken at a time for all tablespaces in one go , one by one tablespace?. If there are difficulties , which way is best?

Use RMAN. It remembers which files are to be recovered from tape. You can backup the way which fits to you most.