Re: Incredible paging on the system
Collalti, Fernando (Fernando.Collalti@orbit.net) wrote:
...
> EXTRAC OF online.log (when the problem occurs) with the
> BUFFERS set to 2000(before it was 200)
> with the new configuration of BUFFERS=5000, CLEANERS=6, LRUS=12)
> Wed Nov 6 08:22:44 1996
> 08:22:48 Onconfig parameter BUFFERS modified from 200 to 2000.
> 08:38:18 Checkpoint Completed: duration was 1 seconds.
> 08:38:34 dynamically allocated new shared memory segment (size 8388608)
> 08:41:05 dynamically allocated new shared memory segment (size 8388608)
> 08:44:05 dynamically allocated new shared memory segment (size 8388608)
> 08:47:25 dynamically allocated new shared memory segment (size 8388608)
> 08:52:27 dynamically allocated new shared memory segment (size 8388608)
> 08:58:16 dynamically allocated new shared memory segment (size 8388608)
> 09:05:44 dynamically allocated new shared memory segment (size 8388608)
> 09:20:54 INFORMIX-OnLine Stopped.> Fernando
> fernando.collalti@orbit.net
Within the span of about 26 min., Informix munched up ( including the
initial size of 8M ) over 64MB of memory. Depending on exactly how much
paging ( swap ) space is configured on your HP, this could easily crash
not only Informix, but HPUX as well.
Memory consumption such as this is not generally a result of 40 data entry
users. Are you building indexes, or otherwise performing massive sorts in
memory?
Set SHMTOTAL in the Config file so that you'll get a shared memory
allocation error before the system crashes ( 40M-50M ). This way,
you'll find the offending operation.
Execute /etc/swapinfo as root to determine the amount of available
paging space. On your system, this sould be at the VERY least 128MB.
Increasing this value will help prolong system integrity during peak
memory usage, however Informix, under normal opereating conditions,
does not willingly release memory segments back to the OS. The only
solution in your case short of adding more real memory is to limit the
maximum amount of memory Informix may use and then tune the engine
so that it will work in such a limited memory environment.
Keep in mind that you don't want Informix Shared memory to be swapped
out to the paging area. This means that your configuration of Informix
SHM must always add up to less than total system memory, regardless of
the amount of paging space.
Kevin Brand