When I start I/O Express with NOAUTOMATIC, I get an "Insufficient Dynamic Memory" error

When I/O Express is started up NOAUTOMATIC, the need for non-paged dynamic memory may be greater than if I/O Express is started dynamically.

When I/O Express attempts to extend the non-paged pool, it triggers a timer routine that prevents I/O Express from spending an enormous amount of time doing the extension. When you start I/O Express, the pool is expanded for each disk that I/O Express caches. In the dynamic mode, the pool is extended only as caching is started on a disk. However, with NOAUTOMATIC, when you specify a disk to be cached, I/O Express is forced to get the non-paged pool that is required to set up the data structures necessary to establish caching. Therefore, the demands to extend the pool are greatly increased.

The first thing to do is to consider running I/O Express dynamically. Dynamic caching is more efficient, because it retains in its cache those data blocks that are most frequently accessed, which are the ones that will give you the greatest performance increase. NOAUTOMATIC should only be used if you must cache a particular disk or disks, and you want to ensure that the cache for that disk is retained, even when there is no activity on that disk. If you want caching to be done only on certain disks, it is much better to exclude specifically the disks you don't want cached and to run I/O Express dynamically on the others.

If you must start up I/O Express in the manual mode, you will have to increase the SYSGEN value of NPAGEDYN and NPAGEVIR. Doing this will force the necessary amount of non-paged memory to be set aside initially and will still allow for future expansion of the pool, if necessary.

If this FAQ helped, please let us know. If you didn't find the answer to your question here please e-mail

Executive Software Europe