Re: Antwort: Re: high paging and slow DB2-database. Please contro l my configur ation
- From: Robert Binkley <leebinkley@xxxxxxxxx>
- Date: Thu, 16 Mar 2006 05:02:06 -0800
Updating environment settings for a partitioned DB2
installation (AIX)
This task describes the environment settings that you
need to update on each computer that will participate
in your partitioned database system.
Procedure
To update AIX environment settings:
Log on to the computer as a user with root authority.
Set the AIX maxuproc (maximum number of processes per
user) device attribute to 4096 by entering the
following command:
chdev -l sys0 -a maxuproc='4096'
1 Set the TCP/IP network parameters on all the
workstations that 1 are participating in your
partitioned database system to the following values. 1
These values are the minimum values for these
parameters. If any of the network-related 1 parameters
are already set to a higher value, do not change it. 1
thewall = 65536
1 sb_max = 1310720
1 rfc1323 = 1
1 tcp_sendspace = 221184
1 tcp_recvspace = 221184
1 udp_sendspace = 65536
1 udp_recvspace = 65536
1 ipqmaxlen = 250
1 somaxconn = 1024
1 To list the current settings of all network-related
1 parameters, enter the following command:
1 no -a | more
1 To set a parameter, enter the follow command:
1 no -o parameter_name=value
where:
1 1 parameter_name represents the parameter you want
to set. 1 value represents the value that you want to
set for this parameter.
For example, to set the tcp_sendspace parameter to
221184, enter the following command:
1 no -o tcp_sendspace=221184
If you are using a high speed interconnect, you must
set the spoolsize and rpoolsize for css0 to the
following values:
spoolsize 16777216
rpoolsize 16777216
To list the current settings of these parameters,
enter the following command:
lsattr -l css0 -E
To set these parameters, enter the following commands:
/usr/lpp/ssp/css/chgcss -l css0 -a
spoolsize=16777216
/usr/lpp/ssp/css/chgcss -l css0 -a
rpoolsize=16777216
If you are not using the /tftpboot/tuning.cst file to
tune your system, you can use the
/opt/lpp/db2_08_01/misc/rc.local.sample sample script
file to update the network-related parameters after
installation. To update the network-related parameters
using the sample script file after installation,
perform the following steps:
Copy this script file to the /etc directory and make
it executable by root by entering the following
commands:
cp /opt/lpp/db2_08_01/misc/rc.local.sample
/etc/rc.local
chown root:sys /etc/rc.local
chmod 744 /etc/rc.local
Review the /etc/rc.local file and update it if
necessary.
Add an entry to the /etc/inittab file so that the
/etc/rc.local script is executed whenever the machine
is rebooted. You can use the mkitab command to add an
entry to the /etc/inittab file. To add this entry,
enter the following command:
mkitab "rclocal:2:wait:/etc/rc.local > /dev/console
2>&1"
Ensure that /etc/rc.nfs entry is included in the
/etc/inittab file by entering the following command:
lsitab rcnfs
Update the network parameters without rebooting your
system by entering the following command:
/etc/rc.local
Ensure that you have enough paging space for a
partitioned installation of DB2 ESE to run. If you do
not have sufficient paging space, the operating system
will kill the process that is using the most virtual
memory (this is likely to be one of the DB2
processes). To check for available paging space, enter
the following command:
lsps -a
This command will return output similar to the
following:
Page Space Physical Volume Volume Group Size %Used
Active Auto Type
paging00 hdisk1 rootvg 60MB 19
yes yes lv
hd6 hdisk0 rootvg 60MB 21
yes yes lv
hd6 hdisk2 rootvg 64MB 21
yes yes lv
We recommend that the paging space available be equal
to twice the amount of physical memory installed on
your computer.
If you are creating a small to intermediate size
partitioned database system, the number of network
file system daemons (NFSDs) on the instance-owning
computer should be close to:
--- "Green, Simon" <Simon.Green@xxxxxxxxxxxxx> wrote:
There really isn't a way to calculate this, as farhttp://publib-b.boulder.ibm.com/redbooks.nsf/portals/UNIX
as I am aware. (I'm sure
there is, actually, but it would be dreadfully
complex.)
Change it to lower values. If there's still too
much paging, make the
values lower again. It's dynamic, so it's easy to
vary it until you get a
value that works for you and you can always put it
back to the original
settings if there's no improvement.
Note that with vmtune the values need to be re-set
after a reboot, so either
place the vmtune command in inittab, or in a script
called from inittab. I
assume that the same applies to vmo, but I'm not
certain.
As I said: typical values in the systems I manage
are minperm=3 maxperm=8.
The most extreme I've got is minperm=1, maxperm=5.
With large amounts of
memory and database applications this is not at all
unreasonable: it still
leaves plenty of memory for normal filesystem access
etc. Your current
settings (10/30) are way too high, unless you have a
LOT of non-DB2 activity
on your system.
There's been lots of discussion of these settings in
the past - including
earlier this year - so you could check through the
archives if you want more
opinions.
--
Simon Green
Altria ITSC Europe s.a.r.l.
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-----Original Message-----
From: IBM AIX Discussion List
[mailto:aix-l@xxxxxxxxxxxxx] On Behalf Of
fmu@xxxxxxxx
Sent: 16 March 2006 11:55
To: aix-l@xxxxxxxxxxxxx
Subject: Antwort: Re: high paging and slow
DB2-database. Please control my
configur ation
o.k. but I change (reduce) minperm and maxperm when
I install the DB2.
Isn't this enough?
Must I decrease this parameter more? For example
maxperm=20 and minperm=5 ?
What is the way to calculate this?
"Green, Simon"
<Simon.Green@xxxx
LTRIA.COM>
An
Gesendet von: IBM
aix-l@xxxxxxxxxxxxx
AIX Discussion
Kopie
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<aix-l@Princeton.
Thema
EDU> Re: high
paging and slow
DB2-database. Please control my
configur
ation
16.03.2006 12:24
Bitte antworten
an
IBM AIX
Discussion List
<aix-l@Princeton.
EDU>
Changing minperm and maxperm is probably the best
place to start. Exact
values will depend on the type and level of activity
on your system but
assuming you don't have anything of significance
other than your DB
application, something like 3/8 would be OK.
(That's a typical value on
our
systems: mostly SAP/Oracle, but it should apply to
DB2 as well.)
You can set the parameters with the vmo command.
(Used to be vmtune, but
in
5.2 vmtune is only there for compatibility and it
invokes vmo and/or ioo.)
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