Monitor chunk I/O activity with the onstat -g iof command

Use the onstat -g iof command to monitor chunk I/O activity, including the distribution of I/O requests against the different fragments of a fragmented table.

The onstat -g iof command displays:
  • The number of reads from each chunk and the number of writes to each chunk
  • I/0 by service level, broken down by individual operation
  • The type of operation
  • The number of times the operation occurred
  • The average time the operation took to complete

If one chunk has a disproportionate amount of I/O activity against it, this chunk might be a system bottleneck.

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