From: Holger.VanKoll@SWISSCOM.COM
Date: Mon Nov 25 2002 - 06:13:40 EST
Hello,
I got a s80 (4.3.3-10, 6cpu, 6gb ram) with 2 oracle-instances. One runs batch-like (processing of large files), the other is interactively used by users.
Those users complain about long response times.
Here is a vmstat 60:
2 6 1560288 706 0 1 0 4455 204014 0 2783 15595 7087 25 12 22 41
2 4 1560572 625 0 1 0 3228 152413 0 2084 13402 4684 29 9 33 28
2 6 1561113 601 0 3 4 2941 142892 0 2157 9283 3806 30 7 27 36
2 5 1563545 605 0 3 32 2983 141270 0 2153 12852 3709 36 9 26 29
2 4 1563780 629 0 2 55 2388 107086 0 1773 10454 2336 32 6 35 27
2 4 1562897 595 0 2 0 1715 77654 0 1667 7207 2933 33 5 37 24
3 8 1563223 607 0 1 0 4670 210713 0 3332 13649 7209 42 13 15 30
5 10 1561365 621 0 5 0 5675 208666 0 3662 17526 8414 51 15 6 28
5 10 1565068 604 0 5 0 5489 214688 0 3684 17836 8516 48 15 9 28
I dont have any system with such a high fr:sr ratio. Did anybody ever notice such a high ratio?
I constantly see lrud in topas with 1-4% cpu; regarding this srīs I dont expect anything else.
So I tried to remove some load from lrud and decreased lrubucket from 131072 to 65536. Users told me responsetime got a bit better.
Earlier I increased minfree from 120 to 600 (as I watched fre getting 0 sometimes), that also improved responsetime. But its still too bad.
As all memory-tuning improved responsetime, memory is (to me) the thing to look at.
The big question: How can I determine how much memory would improve responsetime?
2 things regarding oracle:
The db_blocksize is set to 8kb. Aix vmm writes pages, those are 4kb. I know (and understand) the db blocksize should be equal to or multiples of the "os-blocksize".
But is there any docu that tells when it should be equal and when multiple times? You cant change this size after creating the db, so trial-and-error is no way.
Does oracle support the aix-feature direct I/O? http://publib.boulder.ibm.com/doc_link/en_US/a_doc_lib/aixbman/prftungd/2365c813.htm
Here is vmtune -a output:
nb_mem_pools = 1
nb_frs_per_memp = 2
total_frame_sets = 2
vmm_page_color_on = 0
memory frames = 1572825
maxpin = 1258260
minperm = 31456
maxperm = 62913
maxclient = 1257440
numperm = 63731
numclient = 4
numcompress = 0
maxpin % = 80.0
minperm % = 2.0
maxperm % = 4.0
maxclient % = 79.9
numperm % = 4.1
numclient % = 0.0
numcompress % = 0.0
minpgahead = 4
maxpgahead = 16
minfree = 600
maxfree = 616
pd_npages = 524288
maxrandwrt = 0
numclust = 1
npswarn = 106496
npskill = 26624
numfsbufs = 93
hd_pbuf_cnt = 1056
lvm_bufcnt = 9
lrubucket = 65536
defps = 1
sync_release_ilock = 0
nokilluid = 0
v_pinshm = 0
strict_maxperm = 0
lgpg_regions = 0
lgpg_size = 0
hd_pendqblked = 736
psbufwaitcnt = 70647
fsbufwaitcnt = 519443
rfsbufwaitcnt = 0
Regards, Holger
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