Legato networker incremental backup hangs

Question

Hi All,
I have once a week database level 0 backup and the rest of the days level 1 cumulative backup. Problem I am facing is level 1 backup always hangs, whereas level 0 backup finished in an hour. Here I am posting all possible info I know of to investigate why it hangs.
Rman Script
connect target sys/password@db
connect catalog rman/password@catalog;
run
set command id to 'Inc1_Backup';
allocate channel t1 type 'SBT_TAPE' parms 'ENV=(NSR_SERVER=nw1,NSR_CLIENT=db)';
allocate channel t2 type 'SBT_TAPE' parms 'ENV=(NSR_SERVER=nw1,NSR_CLIENT=db)';
allocate channel t3 type 'SBT_TAPE' parms 'ENV=(NSR_SERVER=nw1,NSR_CLIENT=db)';
allocate channel t4 type 'SBT_TAPE' parms 'ENV=(NSR_SERVER=nw1,NSR_CLIENT=db)';
sql 'alter database backup controlfile to trace';
backup incremental level=1 cumulative
filesperset 50
tag 'Level 1 Backup'
format 'secdb_%T_%s.bak'
(database include current controlfile);
backup archivelog all format 'secdb_arc_%T_%s.bak' ;
delete archivelog until time 'sysdate -2';
release channel t1;
release channel t2;
release channel t3;
release channel t4;
Part of rman log file
connected to target database: db (DBID=<dbid>)
connected to recovery catalog database
executing command: SET COMMAND ID
starting full resync of recovery catalog
full resync complete
allocated channel: t1
channel t1: sid=252 devtype=SBT_TAPE
channel t1: NMO v5.0.0.0
sent command to channel: t1
allocated channel: t2
channel t2: sid=255 devtype=SBT_TAPE
channel t2: NMO v5.0.0.0
sent command to channel: t2
allocated channel: t3
channel t3: sid=523 devtype=SBT_TAPE
channel t3: NMO v5.0.0.0
sent command to channel: t3
allocated channel: t4
channel t4: sid=268 devtype=SBT_TAPE
channel t4: NMO v5.0.0.0
sent command to channel: t4
sql statement: alter database backup controlfile to trace
Starting backup at 27-SEP-10
There is no information after "starting backup" even after 4, 5 hours. The most of the waits are being observed at "SQL*Net message from client". Also, there is no high load, no cpu usage or no disk activity going on. Everything on server appears to be idle. Also, catalog server is Oracle 9i where db server is 10g.
Any idea ? ?

Answer 1

Dear Tycho,
The script executed fine for like more than a year, so that's not the syntax issue. Otherwise, it might have given a syntax error just in the beginning.
The problem has been solved. Issue was the recovery catalog was having entries for many expired backups for more than a year and was never cleaned up. I crosschecked and removed all expired entries and backup now completes faster than even before.
Cheers !