Sunday, January 3, 2010

Adding chunk to dbspace in IBM Informix (IDS) using 'onspaces' utility

Recently I got into problem when there was on space left on dbspace on one of our Informix database. It took me nearly 2 hours of Googling to figure out how to add CHUNK to existing dbspace.

I thinks it would be better to blog it, this might help some other folks or might I need to use it some day when the newly added CHUNK also get full :)

For my setup I do not have the additional hard drive and have a plenty of free space on Unix partition. Therefore I used the unix file as new Chunk.

'onmonitor', oncheck -pe, onstat -d commands can be used to view the status of dbspaces.

Here are the steps to add chunk.

1. First create a chunk file in Unix filesystem and set the permission so that informix user/group have the read/write permission on the file.

touch /export/home/dbspace/billdb_dg/lv_recorddbs11

chmod 660 /export/home/dbspace/billdb_dg/lv_recorddbs11

Note: I run the above commands with 'informix' user or the owner of informix db.

The following example adds a 2GB chunk to recordbs. An offset of 200 kilobytes is specified.

onspaces -a recorddbs -p /export/home/dbspace/billdb_dg/lv_recorddbs11 -o 200 -s 2093150

Here -s 2093150 is specified in KB

The newly added chunk is available immediately.

After you create the chunk, you must perform a level-0 backup of the root dbspace and the dbspace that contains the chunk.


  1. I am a newbie to informix and your blog helped me a lot.thank you very much.

  2. This is the best description of adding a chunk to an existing dbspace that I've found. Thank you for posting this!

  3. yes, very helpful indeed.