Re: AIO and Buffer Waits
Hi Art,
BTR is 48,57 per hour. According to Lester Knutsen should be < 6 per
hour.
BUFFERPOOL looks like that and AUTO:LRU_TUNING is turn on:
BUFFERPOOL
size=2K,buffers=2400000,lrus=60,lru_min_dirty=0.200000,lru_max_dirty=0.400000
AUTO_LRU_TUNING 1
onstat -p (last onstat -z 14 hours ago)
IBM Informix Dynamic Server Version 11.50.FC7W3 -- On-Line -- Up 54
days 01:54:20 -- 8984576 Kbytes
Profile
dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits
%cached
142604256 1410570080 59284431722 99.76 61872253 98433717
227436232 72.80
isamtot open start read write rewrite delete
commit rollbk
52046254582 216281491 457585123 48750470513 17730429 30711047
19268677 18995943 1446067
gp_read gp_write gp_rewrt gp_del gp_alloc gp_free
gp_curs
14 0 9 0 0 0 0
ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes
0 0 0 317120.96 38441.46 134 163
bufwaits lokwaits lockreqs deadlks dltouts ckpwaits
compress seqscans
20157325 126775 1927754927 0 0 5149
6933881 1205132
ixda-RA idx-RA da-RA RA-pgsused lchwaits
66150442 1636318 30850997 97300297 20233621
What would be a reasonable value for lrus?
TIA, Reinhard.
From: Art Kagel [mailto:art.kagel@gmail.com]
Sent: Wednesday, July 13, 2011 12:24 PM
To: Habichtsberg, Reinhard
Cc: informix-list@iiug.org
Subject: Re: AIO and Buffer Waits
Most bufwaits are caused by contention for the LRU queues, so increase
the LRU queues for your buffer caches to maximum first. Use the BTR
calculation and observing activity in onstat -P over time to determine
if you may also need more buffers.
Art
Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
Blog: http://informix-myview.blogspot.com/
Disclaimer: Please keep in mind that my own opinions are my own opinions
and do not reflect on my employer, Advanced DataTools, the IIUG, nor any
other organization with which I am associated either explicitly,
implicitly, or by inference. Neither do those opinions reflect those of
other individuals affiliated with any entity with which I am affiliated
nor those of the entities themselves.
On Wed, Jul 13, 2011 at 2:49 AM, Habichtsberg, Reinhard
<RHabichtsberg@arz-emmendingen.de> wrote:
We see the following waitstates on one of our Informix 11.50FC7W3
servers. He is running OLTP but also Decision Support.
(sum) 81125424549,00
reason aio
(sum) 62105207794,00
reason buffer
(sum) 61713678094,10
reason mt yield n
(sum) 61561288458,60
reason mt yield
(sum) 29339327941,19
reason mt ready
(sum) 15649570039,20
reason running
(sum) 3340893922,100
reason log i/o
(sum) 1550362515,000
reason mt yield 0
(sum) 1439244418,300
reason checkpoint
(sum) 162272243,0000
reason lock
(sum) 157356745,3000
reason mutex
(sum) 21639138,60000
reason full Q
What do you suggest to reduce IO and Bufferwaits. My idea is to increase
the buffers.
TIA,
Reinhard.
_______________________________________________
Informix-list mailing list
Informix-list@iiug.org
http://www.iiug.org/mailman/listinfo/informix-list