Re: Cold Backups in NOMOUNT Stage

Raaj wrote:
> Friends,
> I am fresher in Oracle DBA. I have some few doubts. Pls
> clarify me.
>
> 1) Can we take cold backup in NOMOUNT Stage.
> At nomount stage only pfile is read and SGA is allocated and
> background process are started. So to my knowledge, i think we can take
> backups. Please correct me if i am wrong.
>
> 2) How to monitor LOG SWITCH.
> Is it by monitoring ALERT LOG and by querying V$LOG and
> V$LOGFILE.
>
> 3) If one of my online redolog is corrupted in which it contains more
> than half of REDO entries, how can i recover. Is it a nice thing to
> drop the online log which has more than half of redo entries. How to
> recover the data ie redo entries in redolog in that case.
>
> Thanks,
> erkraj

1. Not possible

just fyi:
nomount --> background processes are started. No files are open mount ---> controlfile is opened
open --> datafiles are opened

2) You can log your checkpoints to the alert by changing an init.ora parameter.

Log switch means checkpoint
Also : archivals are logged in the alert 3)
You can not. If you loose the online redo log you are toast. It is a nice thing to drop the online redo log if you are looking for a career move and want to be kicked out.

-- 
Sybrand Bakker
Senior Oracle DBA