RE: Utilizing shared memory on HPUX 10.20
Try reducing the number of poll threads on your shared memory (ipcshm)
connection from '9' down to as low as you can go. Do you really need 900
shared memory connections?? I know it's good practice to even out the cpuvp
load by creating an equal number of poll threads, but, unfortunately, this
also creates that many (M)essage segments in shared memory. And, especially
in HPUX 10.20, multiple shared memory segments are very bad news.
HTH,
Paul Mosser
P.S. Also check your kernel settings for SHMSEG and SHMMNI...
-----Original Message-----
From: mattb5@ozemail.com.au [mailto:mattb5@ozemail.com.au]
Sent: Tuesday, January 18, 2000 2:51 AM
To: informix-list@iiug.org
Subject: Utilizing shared memory on HPUX 10.20
Hi All,
I am having trouble getting IDS 7.31.UC2 to use more than 1078 Mb's of
shared memory on a HP9000 T500 running HPUX 10.20 despite the fact that
the machine has 1500 Mb's of RAM and vmstat / glance reports > 130 Mb's
of free memory.
I started out trying to increase BUFFERS because the read cache was
hovering on 92% and buffwaits percentage up to 20% Well that was my
plan and it sounded like the next logical step. Problem is when I
increased BUFFERS from 215,625 to 231,250 the engine failed to
initialize with the following error:
20:35:30 Could not create single shared memory segment with residentand non-resident partitions. Proceeding to create 2 shared memory
segments instead.
20:36:21 hpkaioaddseg: ASYNC_ADDSEG failed, errno = 12
20:36:21 Assert Failed: kaiothread() ERROR
20:36:21 Informix Dynamic Server Version 7.31.UC2
20:36:21 Who: Session(0, @, 0, 0)
Thread(172, kaio, 0, 13)
File: kaio.c Line: 2121
OK I understand why the engine needs to create two shared memory
segments, this is normal. But I don't know how to solve the assert
failed. Informix have suggested that I disable KAIO but last time I
tried the performance degraded significantly, so I am not keen to
disable it again. Now Informix are suggesting SHMEM_MAGIC but I can't
see how that will help when the machine only has 1.5 Gb of RAM.
I have applied all of the HPUX patches recommend in the release notes.
Kernel parameter SHMMAX = 1.5 Gb and onconfig SHMTOTAL=0
Onstat -g seg shows:
Informix Dynamic Server Version 7.31.UC2 -- On-Line -- Up 1 days
17:31:26 -- 1094312 Kbytes
Segment Summary:
id key addr size ovhd class blkused blkfree
1541 1381451778 80000000 640016384 10376 V 37265 40862
61700 1381451777 c0cc4000 480559104 8248 R 58656 6
6 1381451779 dd710000 1130496 628 M 138 0
7 1381451780 dd824000 1130496 628 M 133 5
8 1381451781 dd938000 1130496 628 M 131 7
9 1381451782 dda4c000 1130496 628 M 131 7
10 1381451783 ddb60000 1130496 628 M 131 7
11 1381451784 ddc74000 1130496 628 M 131 7
12 1381451785 ddd88000 1130496 628 M 131 7
13 1381451786 dde9c000 1130496 628 M 131 7
14 1381451787 ddfb0000 1130496 628 M 131 7
Total: - - 1130749952 - - 97109 40922
OK I know the virtual segment has a lot of free memory, but at peak
times it's comes close to dynamically adding another segment, which
will also fail with the same error due to memory pressure.
vmstat shows:
procs memory
page faults cpu
r b w avm free re at pi po fr de
sr in sy cs us sy id
33 0 0 10179 32583 8 2 0 0 0 0
0 3804 9391 5580 15 29 55
I coming to the conclusion that I am hitting a the limitation with KAIO
in HP 10.20.
Or am I missing something else?
Would adding more memory to this machine help?
If I add more physical memory, will I be able to allocate it to shared
memory and still keep KAIOON? I can't see how considering the machine
still has > 130Mb's of free memory?
OK, here is my onconfig, running unbuffered logging, the machine has 10
CPU and is a dedicated database server with only 1 instance of
Informix. Please feel free to offer any suggestions, especially if you
see something wrong or stupid with my onconfig.
Thanks and regards
Matthew Byrne.,
onconfig:
ROOTNAME mprootdbs
ROOTPATH /opt/informix/dev/mprootdbs.ln
ROOTOFFSET 0
ROOTSIZE 20000
MIRROR 1
MIRRORPATH /opt/informix/dev/mprootdbsm.ln
MIRROROFFSET 0
PHYSDBS mpplogdbs
PHYSFILE 40000
LOGFILES 30
LOGSIZE 50000
MSGPATH /opt/informix/logs/tpramimsp.mlog
CONSOLE /opt/informix/logs/tpramimsp.clog
ALARMPROGRAM /opt/informix/current/etc/no_log.sh
SYSALARMPROGRAM /opt/informix/current/etc/evidence.sh
TBLSPACE_STATS 1
WSTATS 1
TAPEDEV /dev/rmt/c1t5d0BEST
TAPEBLK 1024
TAPESIZE 70000000
LTAPEDEV /dev/rmt/c2t5d0BEST
LTAPEBLK 1024
LTAPESIZE 70000000
SERVERNUM 1
DBSERVERNAME tpramimsp_shm
DBSERVERALIASES tpramimsp
NETTYPE soctcp,9,100,NET
NETTYPE ipcshm,9,100,CPU
DEADLOCK_TIMEOUT 60
RESIDENT 0
MULTIPROCESSOR 1
NUMCPUVPS 9
SINGLE_CPU_VP 0
NOAGE 1
AFF_SPROC 1
AFF_NPROCS 9
LOCKS 200000
BUFFERS 215625
NUMAIOVPS 2
PHYSBUFF 8
LOGBUFF 8LOGSMAX 40
CLEANERS 127
SHMBASE 0x0
SHMVIRTSIZE 625000
SHMADD 32768
SHMTOTAL 0
CKPTINTVL 1200
LRUS 127
LRU_MAX_DIRTY 1
LRU_MIN_DIRTY 0
LTXHWM 50
LTXEHWM 60
TXTIMEOUT 0x12c
STACKSIZE 32
DD_HASHSIZE 91
OFF_RECVRY_THREADS 10
ON_RECVRY_THREADS 1
DRAUTO 0
DRINTERVAL 90
DRTIMEOUT 90
DRLOSTFOUND /opt/informix/current/etc/dr.lostfound.12
CDR_LOGBUFFERS 128
CDR_EVALTHREADS 1,2
CDR_DSLOCKWAIT -1
CDR_QUEUEMEM 500
BAR_ACT_LOG /tmp/bar_act.log
BAR_MAX_BACKUP 0
BAR_RETRY 1
BAR_NB_XPORT_COUNT 10
BAR_XFER_BUF_SIZE 31
ISM_DATA_POOL ISMData
ISM_LOG_POOL ISMLogs
RA_PAGES 6
RA_THRESHOLD 3
DBSPACETEMP mptmpdbs1,mptmpdbs2,mptmpdbs3
DUMPDIR /tmp
DUMPSHMEM 0
DUMPGCORE 0
DUMPCORE 0
DUMPCNT 1
FILLFACTOR 90
USEOSTIME 1
MAX_PDQPRIORITY 100
DS_MAX_QUERIES 2
DS_TOTAL_MEMORY 8000
DS_MAX_SCANS 100
DATASKIP OFF
OPTCOMPIND 0
ONDBSPACEDOWN 0LBU_PRESERVE 0
OPCACHEMAX 0
HETERO_COMMIT 0
OPT_GOAL -1
DIRECTIVES 1
RESTARTABLE_RESTORE offCDR_LOGDELTA 30
CDR_NUMCONNECT 16
CDR_NIFRETRY 300
CDR_NIFCOMPRESS 0
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