Recovery doesn't see old archivelog backups

Question

I am doing weekly full backups
backup
as compressed backupset
channel=disk1
full
database
include current controlfile
plus archivelog
delete all input;
Point-in-time recovery worked fine using:
set until scn $1 ;
restore database;
recover database delete archivelog;
release channel c1;
alter database open resetlogs;
Untill today, when I tried recovering using backupset that is two weeks old.
Restore database worked fine. But media recovery failed with errors like this:
RMAN-03002: failure of recover command at 09/28/2006 21:06:58
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of log thread 1 seq 10992 lowscn 200869768 found to restore
RMAN-06025: no backup of log thread 1 seq 10991 lowscn 200868902 found to restore
database recovery was unable to find archivelog backups.
What was confusing is that 'list backup' would show me the missing backups as available:
BS Key Size Device Type Elapsed Time Completion Time
1653 497.50K DISK 00:00:01 17-SEP-06
BP Key: 1868 Status: AVAILABLE Compressed: YES Tag: TAG2006_09_17
Piece Name: /disk0/oradata/live/LIVE/backupset/2006_09_17/live_2006_09_17_archivelog_mohtfs3a_1_1.bck
List of Archived Logs in backup set 1653
Thrd Seq Low SCN Low Time Next SCN Next Time
1 10992 200869768 17-SEP-06 200870470 17-SEP-06
I tried all what I could think of to get rman to see those backups.
Finally, I changed computer system time to two weeks ago - and recovery worked !
Why is recovery ignoring old archivelog backups ? How to make recovery see those old files ? Is there a more elegant way to recover to a point in time that doesn't require me to change computer clock ? Using 'set until scn' is the standard way I do it but it seems to work only within a certain time frame.

Answer 1

I don't think that's the problem. I use backupsets to create a copy of database on another machine. So, I never (knock on the wood) do recovery of the database that is being backed up.
This is how the script looks like:
set dbid 123123;
startup nomount
run
allocate channel c1 device type disk;
restore controlfile from autobackup maxdays = 100;
alter database mount;
set until scn 7878787;
restore database;
recover database delete archivelog; -- it fails when it gets to this phase, complaining about missing files
release channel c1;
alter database open resetlogs;
}