Re: RMAN backup size is almost bigger twice than all of tablespace used size?

Thanks for the responses with Stefan, Pierre, Jonathan and Mladen.

Tablespace used size is calculated by the sum(bytes) of total file sizes - sum(bytes) of dba_free_space.

The compression_ratio is 1 from v$backup_set_details.

The archived logs with rman backup is only 20 gb.

Even if no compressed my rman backup I thinks shoule be only 600gb but actually 1280gb, so strange!

Best Regards
Quanwen Zhao

Mladen Gogala <gogala.mladen_at_gmail.com> 于2023年11月16日周四 09:17写道：

> On 11/15/23 10:17, Quanwen Zhao wrote:
>
> Hello Stefan,
>
> Sorry, I forget to mention my RMAN backup is no compression and I've
> checked all of the backup sets by v$backup_set_details that has a column
> compressed. BTW the Archived Log has just only 20 GB, so the datafile of
> rman backup is only 1300 - 20 = 1280 GB, 1280 >> 600 ?
>
> Best Regards
> Quanwen Zhao
>
> How many archive logs did you back up? RMAN doesn't backup just data
> files, if I remember correctly. Some of the databases that I am working
> with use 4GB redo logs. Few hundreds of those can really mess up your
> space, so that you can enjoy your ORA-00257 in the middle of the night. And
> the bad news is that archive logs typically do not compress well.
>
> --
> Mladen Gogala
> Database Consultant
> Tel: (347) 321-1217https://dbwhisperer.wordpress.com
>
>

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