Severe Performance Degradation

[Bill Hassell]

vmstat and swapinfo do not report any memory shortage so you're probably OK there. As mentioned, you can ignore the recommendations about the buffer cache since Informix is raw partitions rather than the more common Oracle filesystem design.

First: did the DBAs code the raw devicefiles into the database design? Raw device files are /dev/vgXXX/r in other words, all the data, root and temp volumes must start with the letter r indicating a raw partition. But since your buffer cache numbers are low, this is probably the case.

The second feature is to use async I/O. This requires several steps which are listed in the attacmhent.

[Stojcevski Dejan]

Hi Bill,
There is no presure on mem/swap from the os side. Problems are arising from the IDS side - that is because it's shared memory is limited by it's configuration - BUFFERS. Also SHMVIRTSIZE can be freely added but IDS has taken all that it needs. Buffer pool alocated to IDS is very small and limited so I guess there is a potentional bottleneck.
However, I would like to thank all participants in this thread for their's time and effort.
Dejan.

[Stojcevski Dejan]

I will close this thread.
Dejan.