What mean NUMAIOVPS

Hi Gurus informix, Can you tell me what does mean parameter NUMAIOVPS and in which situation it must be increased ?? best regards PS: our infx administrator has increase this limit from 6 to 7 ???? P. Gineste

PASCAL_GINESTE@Non-HP-France-om4.om.hp.com wrote: > > > Hi Gurus informix, > > Can you tell me what does mean parameter NUMAIOVPS > and in which situation it must be increased ?? > > best regards > > PS: our infx administrator has increase this limit from 6 to 7 ???? NUMAIOVPS is the tunable that controls how many Asynchronous I/O VPs the engine starts. If you are using COOKED chunks or have Kernel Asynchronous I/O (kaio) disabled or unavailable in your port of IDS then these VPs handle all I/O to/from the chunks. For RAW chunks if kaio is enabled kaio handles these chunks and only cooked chunks and administrative I/O (like the message log files) pass through the AIO VPs. If you have only RAW chunks and kaio on then you only need a few AIO VPs, 4 is usually fine. If you have cooked chunks or no kaio then the number to configure depends on version: 7.1x 2-2.5 per chunk managed 7.2x 1.5-2 per chunk managed 7.3x 1-1.5 per chunk plus a few extras. Art S. Kagel

Hi Pascal, With the NUMAIOVPS config paramater you can define how much Asynchronuous I/O Virtual Processors (= processes) you want to have. With more then one AIO VP you can read/write to several disks in parrallel. If this parameter isn't set Informix defines 2 AIO VP's for every chunk. My experience tells me that the best thing to do is (under most circumstances), to set 1 AIO VP for every active concurrent HDD with chunks and add one for writing to log files etc. This above settings must not be done when you use Kernel AIO. In that case you should only define 1 AIO VP. Greetings, Rob Prop