Performance & checkpoint

Hi All, My database has grown 3 times and the performance is degrading. During the business hours my checkpoint duration is between 1-8 seconds. About two months ago my checkpoint mostly is between 0-1 seconds. I included my onconfig file for you to review. If you have any suggestions I would be appreciated. Thank you. --Wayne # Physical Log Configuration PHYSDBS plogdbs # Location (dbspace) of physical log PHYSFILE 1800000 # Physical log file size (Kbytes) # Logical Log Configuration LOGFILES 50 # Number of logical log files LOGSIZE 20000 # 20MB each Logical log size (Kbytes) NETTYPE tlitcp,1,100,NET # Configure poll thread(s) fornettype NETTYPE ipcstr,1,63,CPU # Configure poll thread(s) for nettype #NETTYPE tlitcp,1,100,CPU # Configure poll thread(s) fornettype #NETTYPE ipcshm,1,63,CPU # Configure poll thread(s) for nettype # above never work DEADLOCK_TIMEOUT 60 # Max time to wait of lock indistributed env. RESIDENT 1 # Forced residency flag (Yes = 1, No = 0) MULTIPROCESSOR 1 # 0 for single-processor, 1 formulti-processor NUMCPUVPS 1 # Number of user (cpu) vps SINGLE_CPU_VP 0 # If non-zero, limit number of cpu vpsto one NOAGE 1 # Process aging AFF_SPROC 1 # Affinity start processor AFF_NPROCS 1 # Affinity number of processors # Shared Memory Parameters LOCKS 5000000 # Maximum number of locks BUFFERS 358000 # Maximum number of shared buffers NUMAIOVPS 1 # Number of IO vps PHYSBUFF 256 # Physical log buffer size (Kbytes) LOGBUFF 32 # Logical log buffer size (Kbytes)LOGSMAX 200 # Maximum number of logical log files CLEANERS 30 # Number of buffer cleaner processes SHMBASE 0xa000000 # Shared memory base address SHMVIRTSIZE 512000 # initial virtual shared memorysegment size SHMADD 16384 # Size of new shared memory segments (Kbytes) SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited CKPTINTVL 300 # Check point interval (in sec) LRUS 12 # Number of LRU queues LRU_MAX_DIRTY 3 # LRU percent dirty begin cleaninglimit LRU_MIN_DIRTY 2 # LRU percent dirty end cleaning limit LTXHWM 50 # Long transaction high water markpercentage LTXEHWM 60 # Long transaction high water mark (exclusive) TXTIMEOUT 0x12c # Transaction timeout (in sec) STACKSIZE 32 # Stack size (Kbytes) OFF_RECVRY_THREADS 10 # Default number of offline workerthreads ON_RECVRY_THREADS 1 # Default number of online workerthreads # Data Replication Variables DRINTERVAL 30 # DR max time between DR buffer flushes (in sec) DRTIMEOUT 30 # DR network timeout (in sec) DRLOSTFOUND /usr2/informix/etc/dr.lostfound # DR lost+found filepath # CDR Variables CDR_LOGBUFFERS 2048 # size of log reading buffer pool (Kbytes) CDR_EVALTHREADS 1,2 # evaluator threads (per-cpu-vp,additional) CDR_DSLOCKWAIT 5 # DS lockwait timeout (seconds) CDR_QUEUEMEM 4096 # Maximum amount of memory for any CDR queue (Kbytes)CDR_LOGDELTA 30 # % of log space allowed in queue memory CDR_NUMCONNECT 16 # Expected connections per server CDR_NIFRETRY 300 # Connection retry (seconds) CDR_NIFCOMPRESS 0 # Link level compression (-1 never, 0 none, 9 max) # Read Ahead Variables RA_PAGES 32 # Number of pages to attempt to read ahead RA_THRESHOLD 30 # Number of pages left before next group FILLFACTOR 90 # Fill factor for building indexes # method for OnLine to use when determining current time USEOSTIME 0 # 0: use internal time(fast), 1: get time from OS(slow) # Parallel Database Queries (pdq) MAX_PDQPRIORITY 100 # Maximum allowed pdqpriority DS_MAX_QUERIES # Maximum number of decision supportqueries DS_TOTAL_MEMORY # Decision support memory (Kbytes) DS_MAX_SCANS 1048576 # Maximum number of decision supportscans DATASKIP off # List of dbspaces to skip OPTCOMPIND 0 # To hint the optimizer DIRECTIVES 1 # Optimizer DIRECTIVES ON (1/Default) or OFF (0) ONDBSPACEDOWN 1 # Dbspace down option: 0 = CONTINUE, 1 = ABORT, 2 = WAITLBU_PRESERVE 1 # Preserve last log for log backup OPCACHEMAX 0 # Maximum optical cache size (Kbytes) # The following are undocumented and needed to increase size of the data # dictionary cache. These lines must be added manually to the onconfig file DD_HASHSIZE 503 # Length of DD Hash DD_HASHMAX 20 # Width of DD Hash # DS_HASHSIZE 503 DS_POOLSIZE 500