The onstat -d utility

The onstat -d utility lists all dbspaces, blobspaces, and sbspaces and the following information for the chunks within those spaces.
  • The address of the chunk
  • The chunk number and associated dbspace number
  • The offset into the device (in pages)
  • The size of the chunk (in pages)
  • The number of free pages in the chunk
  • The path name of the physical device

If you issue the onstat -d command on an instance with blobspace chunks, the number of free pages shown is out of date. The tilde (~) that precedes the free value indicates that this number is approximate. The onstat -d command does not register a blobpage as available until the logical login which a deletion occurred is backed up and the blobpage is freed. Therefore, if you delete 25 simple large objects and immediately run onstat -d, the newly freed space is not in the onstat output.

To obtain an accurate number of free blobpages in a blobspace chunk, issue the onstat -d update command. For details, see The onstat -d update option.

In onstat -d update output, the flags column in the chunk section provides the following information:
  • Whether the chunk is the primary chunk or the mirror chunk
  • Whether the chunk is online, is down, is being recovered, or is a new chunk

For an example of onstat -d output, see information about the onstat utility in the Informix® Administrator's Reference.

Important: You must perform a level-0 backup of the root dbspace and the modified dbspace before mirroring can become active and after turning off mirroring.