RMan Backup to Disk Options

Question

Hello,
In Oracle 8.17 on Sun using RMan with a FULL DATABASE backup to Disk can someone please explain:
1. How to specify a tablespace(s) to NOT backup?
2. How to compress the RMan file during the backup (I am low on diskspace).
3. How to break the backup into two pieces and specify a different location for both?
I am not sure if the above are possible. Thanks for you help.
Thanks very much for your advice,
Michael42

Answer 1

Re your 2nd question :-
I've looked into RMAN and on the fly compression ( unix/linux).
It looks like it can't be done well not easily, ( check AskTom or dbForumns if you like).
Several others have tried and RMAN defeats you each time, the problem is that RMAN can't be made to write to STDOUT or STDERR or STD<anything> and thus any "on the fly" compression tools ie:gzip|bzip2| compress just doesn't get a chance at it.
If you are prepared to do some heavy scripting you can use a named pipe into a fixed file name and apply compression through the pipe, but it's a hell of a lot of work and there's a lot that can go wrong.
Re: Your 3rd question :-
Not sure that this will help you 100%, but it may give you an idea or 2.
I splice the DB backup like so; database on one volume and archivelogs on another as follows ...
run {
allocate channel ch1 type disk format '/backupdir1/b_%u_%s_%p.db';
allocate channel ch2 type disk format '/backupdir2/b_%u_%s_%p.arch';
sql 'alter system switch logfile';
set limit channel ch1 kbytes 1024000;
backup (database include current controlfile channel ch1);
set limit channel ch2 kbytes 1024000;
backup (archivelog all delete input channel ch2);
I also limit the size of the pieces.
Hope you get your problems sorted.