Cache

Hello, I am looking for some information on tuning NF, customer is currently running on a PII-400with 328MB memory, and Raid-1 (mylex) controller. I understand that there is a technique for adjusting the cache for both the server and the client. Can someone point me to a technical discussion or guideline on adjusting these… As I read further into the discussion groups here… I see that Navision is not easily CPU bound… But this is my clients situation… When a large transaction comes through (and this is viewed through the NT performance monitor) it pegs the cpu… If several large trans come through, there is additional delay… Could there be other causes of this symptom… I know the user has made extensive table modifications to the system… Is there a general performance cookbook for NF?? Thanks in advance for any replies… Gary Redshaw Managing Partner future Vision inc…

We’re having performance problems and need information about tuning and monitoring tools. The system is slow. We’ve been told by support to open up write cache, which conflicts with documentation saying not to open up write cache unless there is a UPS (uninterrupted power source/supply). This is not comfortable; Data integrity is our primary concern and we cannot depend on batteries or UPS. There is construction in our area, and power interruptions and spikes are not unexpected. I’m not a Navision DBA, so am not familiar with NA performance, monitor, tuning, and trace tools. Any information is appreciated. My e-mail address is: Linda@Pets.com. Thanks.

Definitely you should tweak the cache. There is “CACHE” and also “COMMITCACHE”. Go to the services window and stop the NAVISION service. Then on the parameter field type: CACHE=164000,COMMITCACHE=YES Start the service again. What this does is to create a memory (RAM) cache for your database (164000K or 164 megs ). It should speed your disk access. The amount of memory is up to you. Then the commitcache=yes parameter automatically sets some of that RAM for writing updates. That is not the same thing as opening up the write cache. But it will speed up your server. The amount of CACHE should be less that the total amount of RAM installed and the number of services running.

COMMITCACHE=yes is the same thing as write cache to Navision. Of course, there are other kinds of write cache (like on the hard disk controller card) but these should generally be disabled with Navision and most other database servers. You have to be careful not to set the CACHE too high. This can adversely affect performance. It is not as simple as making the number smaller than physical RAM. It must be small enough to make sure that a page fault does not occur very often while trying to use the CACHE. Jim Hollcraft aka Skater drilldot.com Unauthorized Navision News Link Edited by - Jim Hollcraft on 5/29/00 11:36:42 PM