Problem flushing shared pool on 11.1.0.7 HP-UX Itanium

We have a HP-UX Itanium Server with 28Gb of memory, 4 cores, Oracle 11.1.0.7. it often hangs waiting for flushing shared pool, manually or automatically. Memory Target is 18Gb.

the ASMM set the following parameters

__db_cache_size=5368709120
__java_pool_size=67108864
__large_pool_size=67108864
__oracle_base='/prod01/app/oracle'#ORACLE_BASE set from environment
__pga_aggregate_target=6710886400
__sga_target=12616466432
__shared_io_pool_size=0
__shared_pool_size=6912212992
__streams_pool_size=67108864

when the shared pool is full, sometimes we get that most processes wait for library cache: mutex X. It takes up to 2 hours to flush the shared pool and sometimes we have to kill the smon because the instances doesn't accept any conection to shutdown the instance.

Has anybody had issues with flushing the shared pool?

-- 
Alfonso Leon

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