IDS Forum

Re: IDS 11 - Slowness with DirectIO

Posted By: John Miller iii
Date: Wednesday, 3 June 2009, at 1:53 p.m.

In Response To: Re: IDS 11 - Slowness with DirectIO (MIKE MAGIE)

For those on version 11 who desire to use cooked chunks you can use
the sql admin api and you do not have to create the files a head of time.
Here are a few examples, for more examples see
$INFORMIXDIR/demo/sysadmin/system_setup.sql

===================EXAMPLE #1==========================
dbaccess sysadmin -
execute function task( "create dbspace", "dbspace1",
"/work/CHUNKS/dbspace1", 0, "2 GB");

Another way to create a set of dbspaces and chunks are the following:
===================EXAMPLE #2==========================
database sysadmin;

{ **** Create a table of dbspaces which are to be created ****}
create table dbspaces

(

type varchar(255),

dbspace varchar(255),

path varchar(255),

offset varchar(255),

size varchar(255),

);

insert into dbspaces values
("sbspace", "sbspace", "$INFORMIXDIR/CHUNKS/sblob1", 0 , "50 MB" );
insert into dbspaces values
("dbspace", "dbspace1", "$INFORMIXDIR/CHUNKS/dbspace1", 0 , "50 MB" );
insert into dbspaces values
("dbspace", "dbspace2", "$INFORMIXDIR/CHUNKS/dbspace2", 0 , "50 MB" );
insert into dbspaces values
("dbspace", "physdbs", "$INFORMIXDIR/CHUNKS/physdbs", 0 , "50 MB" ););
insert into dbspaces values
("dbspace", "logdbs", "$INFORMIXDIR/CHUNKS/logdbs", 0 , "50 MB" );););
insert into dbspaces values
("tempdbspace", "tempdbs", "$INFORMIXDIR/CHUNKS/tempdbs", 0 , "10 MB" );
insert into dbspaces values
("blobspace", "bspace1", "$INFORMIXDIR/CHUNKS/blobdbs", 0 , "50 MB" ););

{ **** Create a table of chunks which are to be created **** }
create table chunks

(

dbspace varchar(255),

path varchar(255),

offset varchar(255),

size varchar(255),

);
insert into chunks values
("dbspace1", "$INFORMIXDIR/CHUNKS/chunk",0 , "10 MB" );
insert into chunks values
("dbspace1", "$INFORMIXDIR/CHUNKS/chunk2",0 , "10 MB" );

{**** Create all the dbspaces ****}
SELECT task( "create "|| type , dbspace, path, size, offset)

FROM dbspaces;

{**** Add the chunks to the dbspaces ****}
select task("add chunk", dbspace, path, size, offset) from chunks;

John F. Miller III
STSM, Support Architect
miller3@us.ibm.com
503-578-5645
IBM Informix Dynamic Server (IDS)

ids-bounces@iiug.org wrote on 06/03/2009 10:34:14 AM:

> [image removed]
>
> Re: IDS 11 - Slowness with DirectIO [15928]
>
> MIKE MAGIE
>
> to:
>
> ids
>
> 06/03/2009 10:35 AM
>
> Sent by:
>
> ids-bounces@iiug.org
>
> Please respond to ids
>
> Unmounted space would be considered raw - which, since you are on
> Linux is not
> what you want. You want to use a mounted file system to create your
dbspaces
> and chunks. If for example you had a file system called /dev/sdb and it
was
> 100 gig you could use the 'touch' command to create a bunch of files that

> would be used for chunks - and optionally create links to the files.
>
> So let's say you have mounted space and called it /dev/sdb, and the sdb
> directory has 100 gig. You can create, using the touch command 50 files
that
> will all end up being your chunks. Using symbolic links in this example,
get
> ya a little script that creates the 50 files, changes their permissions
> accordingly, and links them to symbolic links - this is a ksh example:
>
> #!/usr/bin/ksh
>
> #script to create 50 files and links to be used
> #for 2 gig Informix chunks.
>
> i=1
>
> while ((i <=50));
> do
>
> touch /dev/sdb/c$i;
>
> chown informix /dev/sdb/c$i
>
> chgrp informix dev/sdb/c$i
>
> chmod 660 /dev/sdb/c$i
>
> ln -s /dev/sdb/c$i /informix/dev/chunk$i
>
> ((i=i+1));
> done
>
> There's an easier way to do the permissions thing but this works. Once
you
> have your 50 files you can use onspaces to create your chunks. Some folks

> script this also - and you may feel comfie doing that. The onspaces cmd
to
> create a dbspace is:
>
> onspaces -c -d dbspace_name -p /informix/dev/chunk# -o 0 -s size
>
> Look closely at the documentation for onspaces before your run anything.
Look
> closely at the doc anyways.
>
> MM
>
>
>
*******************************************************************************

> Forum Note: Use "Reply" to post a response in the discussion forum.
>

Messages In This Thread

• IDS 11 - Slowness with DirectIO
  MARK NEWNAM -- Tuesday, 2 June 2009, at 2:42 p.m.
  • Re: IDS 11 - Slowness with DirectIO
    MIKE MAGIE -- Tuesday, 2 June 2009, at 3:06 p.m.
  • Re: IDS 11 - Slowness with DirectIO
    Art Kagel -- Tuesday, 2 June 2009, at 5:34 p.m.
    • Re: IDS 11 - Slowness with DirectIO
      MARK NEWNAM -- Wednesday, 3 June 2009, at 9:08 a.m.
      • Re: IDS 11 - Slowness with DirectIO
        Art Kagel -- Wednesday, 3 June 2009, at 9:41 a.m.
      • Re: IDS 11 - Slowness with DirectIO
        MIKE MAGIE -- Wednesday, 3 June 2009, at 1:34 p.m.
        • Re: IDS 11 - Slowness with DirectIO
          John Miller iii -- Wednesday, 3 June 2009, at 1:53 p.m.

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