Re: KAIO clarification.

Bruce Cota (cota@dpg.rnb.com) wrote: : Hello folks, I could use a little clarification about using KAIO under : SOlaris. We are running On-line 7.11 under Solaris 2.4. An informix : engineer told us that we should set NUMAIOVPS to use more than one : AIOVP and this would have a major impact on performance. However: : - Everything I have read in the manuals and in Suto's book : indicates that we should not set NUMAIOVPS if we are using : KAIO (Kernel Asynchronous IO). Set it to 1. : - Everything I have read indicates that KAIO will automatically : be used if our kernel supports it and we are using raw devices : (which we are). True. : - The Informix release notes for Solaris say that "Kernel AIO : is a standard feature of Solaris 2.4 and is supported" Again, true. : - Suto's book says that onstat -g ioq will show a "kio queue" : if and only if we're using KAIO. Well, I did onstat -g ioq : and didn't see a kio queue, but onstat -g ath does show : a number of aio vps. Don't know. : Can somebody clarify this for me? --- how do I know wether we are : actually using KAIO, and if we're not, what do I have to do start : using KAIO? Issue the command "onstat -g ath". If you see any threads with a name of "kio" or "kaio" (can't remember which), then you are running with kaio. Kaio threads can be found running on the cpu vps. You will have one kaio thread for every cpu vp configured in your system. Also, make sure that the environment variable "KAIOOFF" is not set in your environment prior to starting OnLine.