Dear Sirs,

Informix IDS 7.24 Online.log -> look:
--------------------------------------------------------------------------
20:26:11 Checkpoint Completed: duration was 2 seconds.
20:32:11 Checkpoint Completed: duration was 59 seconds.
20:37:11 Checkpoint Completed: duration was 0 seconds.
20:42:11 Checkpoint Completed: duration was 0 seconds.
20:47:12 Checkpoint Completed: duration was 1 seconds.
20:52:13 Checkpoint Completed: duration was 0 seconds.
20:57:51 Checkpoint Completed: duration was 37 seconds.
21:03:30 Checkpoint Completed: duration was 38 seconds.
21:09:00 Checkpoint Completed: duration was 30 seconds.
21:14:56 Checkpoint Completed: duration was 56 seconds.
21:21:52 Checkpoint Completed: duration was 115 seconds.
21:27:20 Checkpoint Completed: duration was 29 seconds.
21:32:21 Checkpoint Completed: duration was 0 seconds.
21:37:32 Checkpoint Completed: duration was 3 seconds.
21:43:05 Checkpoint Completed: duration was 32 seconds.
21:49:25 Checkpoint Completed: duration was 80 seconds.
----------------------------------------------------------------------------
I think i dont must tell you what the users told me....

Whats the problem?

A little short on the information, aren't we?

Let's start with:

What OS?
How many cleaners?
LRU_MAX_DIRTY?
LRU_MIN_DIRTY?
Did this just start?

What OS?
unix true 64 4.0 on a Alpha4100 machine

CLEANERS 3
LRU_MAX_DIRTY 60
LRU_MIN_DIRTY 50

Is there any rule how to configure the "onconfig.std" file to tune
the system up??

How to configure the BUFFERS?

As a start:

Bump your cleaners up to one per dbspace.

Set lru_max_drity to 3
set lru_min_dirty to 1

You checkpoint problem is related to the number of dirty pages you have, and the time it takes to flush them, when a checkpoint occurs - either by timer or plog full. By setting the lru cleaner threshold values lower you start to clean as soon as things get dirty.

look at onstat -F, you want to see LRU writes, not chunk writes or (heaven) forground writes.

Now i have just updadet my onconfig!
Must the Server or the Database be restartet so that
these changes take effect??

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onstat -F

INFORMIX-OnLine Version 7.24.FC4 -- 169464 Kbytes

Fg Writes LRU Writes Chunk Writes
0 18822 312859

address flusher state data
206748688 0 I 0 = 0X0
206748ce8 1 I 0 = 0X0
206749348 2 I 0 = 0X0
2067499a8 3 I 0 = 0X0
states: Exit Idle Chunk Lru
-------------------------------------------------------------------------

Yes - you have to bounce informix. Notice the high number of chucnk writes? You should see the writes move to LRU writes.