Please pardon my total lack of Informix expertise...but I work in a shop that let go their only informix savvy guy and now someone has asked me to figure out (1) which physical disk drives house the informix dbspaces and (2) determine if they are mirrored and then (3) come up with a plan to spread the dbspaces in a way that take advantage of multiple drives if they are clumped together.

What I really need help with is task number 1...I dont even know where to start. Someone please help?!?! Also, anyone know of a good "Informix for Dummies" type FAQ that is AIX specific?
-thanks

Hi,
try onstat -d for first informations.

Got excited for a second, but that gives me a list of "chunks" that I am not sure how to interpret or tie back to physical disk info. The output I am getting looks like this (from onstat -d):

700000030e657a8 40 24 32 524255 524142 PO- /dev/chunk40
700000030e65928 41 6 32 524255 524252 PO- /dev/chunk41
700000030e65aa8 42 26 32 524255 85873 PO- /dev/chunk42

Is there something here that will help determine pdisks? Thanks for trying either way.
-dnix

Hi,
this section with PO- must be the flags, this tell you chunk is Primary and Online, no Mirror. Pathname the name where the dbspaces/chunks are located. The 2 columns in front of PO- are the size of chunk and whats free of it in pages.

/dev/chunk42 is the name of a part of a disk on your system, maybe it is a symbolic link. Anyway it is not mounted.

The following will be very helpful:

onstat link

AIX Link

The Informix Handbook - ISBN 0130122475

It's always possible that these physical devices are mirrored on OS or Hardware level.

Find out if this server is using raid - if it is then most of your questions will be answered (striping/mirroring ...). If you are not familiar with raid - check out the following link:

raid

Do you have a hardware/software specifications document for this server ? If not, this would be a good time to create/maintain one.

It sounds like what they are asking is, can you take the pdisk and determine what chunk it is linked to. Once you have that information, it is easy to determine where it lies on the database. I suggest that you get training or have your company hire a DBA to help you if you have questions.

There is no way in determining what chunk is allocated to a certain physical device, starting from the device, because a chunk doesn't neccessary start at the beginning of the device. There is an offset!

best way is to start from onstat -d and follow the symboloc links...

With smit you can finally determine what fysical device is linked to a logical volume.

Hello,

I need the same information (1) as DNIX.... so i run onstat -d, and got:

(...)
32d8ec028 156 9 50 1000000 66647 PO- /apps/informix/databases/dbdata3_43
(...)

looking /apps/informix/databases/dbdata3_43

lrwxrwxrwx 1 root other 17 Feb 15 2007 /apps/informix/databases/dbdata3_43 -> /dev/md/rdsk/d326

and looking /dev/md/rdsk/d326

lrwxrwxrwx 1 root root 38 Feb 23 2007 /dev/md/rdsk/d326 -> ../../../devices/pseudo/md@0:0,326,raw


so... what "devices/pseudo/md@0:0,326,raw" means ???

tks!

Hi,
that looks like you do have symbolic links. There must be a file: "devices/pseudo/md@0:0,326,raw" on the engine.

yes, exist:

crw-rw-r-- 1 informix informix 85,326 Feb 23 2007 /devices/pseudo/md@0:0,326,raw

but what it means??

i know that crw.. means that the entry is a character special file.. but what about md@0:0,326,raw

I need to know the physically disk, and the total/free memory n this disk..

tks

Perhaps this script will help, it's called "extract_onspaces.sh" and it will give you a list of the onspaces commands that were used to create the dbspaces.

Change the .txt suffix to .sh and chmod 777 extract_onspaces.sh, and the resulting "make_chunks" file may help.