gh_chunks and SHHMAX

From: <jeffrey.s.horvath_at_ccmail.census.gov>
Date: Fri, 24 Apr 1998 11:28:14 -0500

     Need to know who to set gh_chunks and what effect this would have
     on SHHMAX. DU 4.0B 6Gig of memory. Large Oracle 7.3.3 database.
     
     Hoping you could shed some light on following:
     
     The ipc paramaters for the sites new 8400 are:
     
     ipc: loaded and configured
     fabu01# /sbin/sysconfig -q ipc
     ipc:
     msg-max = 8192
     msg-mnb = 32768
     msg-mni = 2048
     msg-tql = 8192
     shm-max = 1069547520
     shm-min = 1
     shm-mni = 128
     shm-seg = 32
     sem-mni = 512
     sem-msl = 400
     sem-opm = 400
     sem-ume = 400
     sem-vmx = 32767
     
     fabu01# /sbin/sysconfig -q vm
     vm:
     ubc-minpercent = 5
     ubc-maxpercent = 15
     ubc-borrowpercent = 20
     ubc-maxdirtywrites = 5
     ubc-nfsloopback = 0
     vm-max-wrpgio-kluster = 32768
     vm-max-rdpgio-kluster = 16384
     vm-cowfaults = 4
     vm-mapentries = 400
     vm-maxvas = 1073741824
     vm-maxwire = 16777216
     vm-heappercent = 7
     vm-vpagemax = 16384
     vm-segmentation = 1
     vm-ubcpagesteal = 24
     vm-ubcdirtypercent = 10
     vm-ubcseqstartpercent = 50
     vm-ubcseqpercent = 10
     vm-csubmapsize = 1048576
     vm-ubcbuffers = 256
     vm-syncswapbuffers = 128
     vm-asyncswapbuffers = 4
     vm-clustermap = 1048576
     vm-clustersize = 65536
     vm-zone_size = 0
     vm-kentry_zone_size = 16777216
     vm-syswiredpercent = 80
     vm-inswappedmin = 1
     vm-page-free-target = 128
     vm-page-free-swap = 74
     vm-page-free-min = 20
     vm-page-free-reserved = 10
     vm-page-free-optimal = 74
     vm-page-prewrite-target = 256
     dump-user-pte-pages = 0
     kernel-stack-guard-pages = 1
     vm-min-kernel-address = 18446744065119617024
     malloc-percpu-cache = 1
     contig-malloc-percent = 20
     vm-aggressive-swap = 0
     vm-map-index-count = 64
     vm-map-index-rebalance = 128
     vm-map-index-enabled = 1
     vm-map-index-hiwat = 4
     vm-map-index-lowat = 2
     new-wire-method = 1
     vm-segment-cache-max = 50
     vm-page-lock-count = 512
     gh-chunks = 0
     gh-min-seg-size = 8388608
     gh-fail-if-no-mem = 1
     
     
     This says that SHMMAX is 1069547520. The default setting is 4194304.
     When I issue the tstshm command I get following:
     
     fabu01 (ora) /apps/oracle/product/7.3.3 >tstshm Number of segments
     gotten by shmget() = 50 Number of segments attached by shmat() = 31
     
     Odd-sized segments are rounded up to even size Segments attach at
     higher addresses
     
     Default shared memory address = 0x10000 Lowest shared memory address
     = 0x10000 Highest shared memory address = 0x11fc10000
     
     Total shared memory range = 4831838208 (0x120000000) Total shared
     memory attached = 134217696 (0x7ffffe0) Largest single segment size
     = 4194304 (0x400000) Segment boundaries (SHMLBA) = 8192
     (0x2000)
     
     
     Why is not the "Largest single segment size" larger? Will this effect
     performance.
     
     Thanks,
Received on Fri Apr 24 1998 - 17:33:42 NZST

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