Could someone give me some direction?

I have an IBM F50 with 512Mb, 12Gb database on Raid 5. It is version 7.30.UC7-1 on AIX 4.2.1. I am getting a lot of bufwaits. I have been moving the LRU's up (like Art suggests). I am currently at 20% bufwaits, and it has been that way regardless of the number of LRU's. I started with 8 and have tried 25, 35, 55 ,65, and 75 with little or no difference. I know that the stats show it has only been up 2 days, but even as time goes on (week or two) it doesn't get any better. Virtual memory on the system looks good - mostly used with no extra segments. There are about 100 sessions in the system during the day. It is an OLTP system (7am - 5pm - with some nightly cron jobs), and checkpoints are <10 seconds - mostly 5-7 seconds. Of course, all suggestions are welcome. TIA Chris Here is the info: Informix Dynamic Server Version 7.30.UC7 -- On-Line -- Up 2 days 23:41:43 -- 165840 Kbytes Profile dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached 19770060 6487568 815370961 97.58 825159 1951377 14254180 94.21 isamtot open start read write rewrite delete commit rollbk 498409661 4997177 29808549 380436203 10570018 370240 155382 234777 310 gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs 0 0 0 0 0 0 0 ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes 0 0 0 52882.02 4328.88 594 1898 bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans 2816365 54 606837042 0 0 2212 24546 331939 ixda-RA idx-RA da-RA RA-pgsused lchwaits 4695176 60751 6148850 10824249 60306 Informix Dynamic Server Version 7.30.UC7 -- On-Line -- Up 2 days 23:41:49 -- 165840 Kbytes Configuration File: /usr/informix/etc/onconfig.rds #************************************************************************** # # INFORMIX SOFTWARE, INC. # # Title: onconfig.std # Description: INFORMIX-OnLine Configuration Parameters # #************************************************************************** # Root Dbspace Configuration ROOTNAME rootdbs # Root dbspace nameROOTPATH /dev/infmx/rootdbs # Path for device containing root dbspace ROOTOFFSET 0 # Offset of root dbspace into device (Kbytes) ROOTSIZE 140000 # Size of root dbspace (Kbytes) # Disk Mirroring Configuration Parameters MIRROR 0 # Mirroring flag (Yes = 1, No = 0) MIRRORPATH # Path for device containing mirroredroot MIRROROFFSET 0 # Offset into mirrored device (Kbytes) # Physical Log Configuration PHYSDBS physdbs # Location (dbspace) of physical log PHYSFILE 100000 # Physical log file size (Kbytes) # Logical Log Configuration LOGFILES 40 # Number of logical log files LOGSIZE 4000 # Logical log size (Kbytes) # Diagnostics MSGPATH /usr/informix/online.log # System message log file path CONSOLE /dev/console # System console message path ALARMPROGRAM /usr/informix/etc/no_log.sh # Alarm program path # System Archive Tape Device TAPEDEV /dev/rmt0 # Tape device path TAPEBLK 1024 # Tape block size (Kbytes) TAPESIZE 12288000 # Maximum amount of data to put on tape (Kbytes)#TAPESIZE 3999500 # Maximum amount of data to put on tape (Kbytes) # Log Archive Tape Device LTAPEDEV /dev/null # Log tape device path LTAPEBLK 16 # Log tape block size (Kbytes) LTAPESIZE 10240 # Max amount of data to put on log tape (Kbytes) # Optical STAGEBLOB # INFORMIX-OnLine/Optical staging area # System Configuration SERVERNUM 2 # Unique id corresponding to a OnLineinstance DBSERVERNAME rds_shm # Name of default database server DBSERVERALIASES rds_tcp # List of alternate dbservernames DEADLOCK_TIMEOUT 60 # Max time to wait of lock indistributed env. RESIDENT 0 # Forced residency flag (Yes = 1, No = 0) MULTIPROCESSOR 1 # 0 for single-processor, 1 formulti-processor NUMCPUVPS 2 # Number of user (cpu) vps SINGLE_CPU_VP 0 # If non-zero, limit number of cpu vpsto one NOAGE 1 # Process aging AFF_SPROC 0 # Affinity start processor AFF_NPROCS 0 # Affinity number of processors # Shared Memory Parameters LOCKS 80000 # Maximum number of locks BUFFERS 30000 # Maximum number of shared buffers NUMAIOVPS 1 # Number of IO vps PHYSBUFF 120 # Physical log buffer size (Kbytes) LOGBUFF 32 # Logical log buffer size (Kbytes)LOGSMAX 40 # Maximum number of logical log files CLEANERS 11 # Number of buffer cleaner processes SHMBASE 0x30000000 # Shared memory base address SHMVIRTSIZE 38000 # initial virtual shared memorysegment size SHMADD 8192 # Size of new shared memory segments (Kbytes) SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited CKPTINTVL 270 # Check point interval (in sec) LRUS 55 # Number of LRU queues LRU_MAX_DIRTY 10 # LRU percent dirty begin cleaninglimit LRU_MIN_DIRTY 5 # 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) # System Page Size # BUFFSIZE - OnLine no longer supports this configuration parameter. # To determine the page size used by OnLine on your platform # see the last line of output from the command, 'onstat -b'. # Recovery Variables # OFF_RECVRY_THREADS: # Number of parallel worker threads during fast recovery or an offline restore. # ON_RECVRY_THREADS: # Number of parallel worker threads during an online restore. OFF_RECVRY_THREADS 10 # Default number of offline workerthreads ON_RECVRY_THREADS 1 # Default number of online workerthreads # Data Replication Variables # DRAUTO: 0 manual, 1 retain type, 2 reverse type DRAUTO 0 # DR automatic switchover DRINTERVAL 30 # DR max time between DR buffer flushes (in sec) DRTIMEOUT 30 # DR network timeout (in sec) DRLOSTFOUND /usr/informix/etc/dr.lostfound # DR lost+found filepath # CDR Variables CDR_LOGBUFFERS 2048 # size of log reading buffer pool (Kbytes) CDR_EVALTHR

See comments below . . . Chris Burton wrote: > > I have an IBM F50 with 512Mb, 12Gb database on Raid 5. It is version > 7.30.UC7-1 on AIX 4.2.1. I am getting a lot of bufwaits. I have been > moving the LRU's up (like Art suggests). I am currently at 20% > bufwaits, and it has been that way regardless of the number of LRU's. > I started with 8 and have tried 25, 35, 55 ,65, and 75 with little or > no difference. I know that the stats show it has only been up 2 days, > but even as time goes on (week or two) it doesn't get any better. > Virtual memory on the system looks good - mostly used with no extra > segments. There are about 100 sessions in the system during the day. > It is an OLTP system (7am - 5pm - with some nightly cron jobs), and > checkpoints are <10 seconds - mostly 5-7 seconds. Of course, all > suggestions are welcome. > I'm doing some testing now for general system performance. It was induced by a large number of bufwaits after running many report jobs (4gl). I've found that if BUFFERS isn't set high enough that extra LRUs may not help much. I dropped my (test) bufwaits from 100% to 20% just by increasing BUFFERS. See below for additional stuff. ...snipped... > BUFFERS 30000 # Maximum number of shared buffers BUFFERS could be bigger . . . about 50000 > NUMAIOVPS 1 # Number of IO vpsRunning KAIO??? > LRU_MAX_DIRTY 10 # LRU percent dirty begin cleaning> limit > LRU_MIN_DIRTY 5 # LRU percent dirty end cleaning limit Maybe reset to 4 / 2. > RA_PAGES 8 # Number of pages to attempt to read> ahead > RA_THRESHOLD 4 # Number of pages left before next> group Depending on the speed of the disks, maybe increase these numbers. But I'm not sure about RAID5 . . . Just a few things to think about . .. John Carlson Informix DBA WHSmith USA