KAIO problems on SCO 5.0.4

We upgraded the SCO box of a customer from a dual pII to a 4 x XeonII. We also raised the memory from 512Mb to 1Gb. Of course we increased the BUFFERS from 50000 to 150000. Informix seemed to run fine, until we checked the online.log. Hundreds of lines complaining about KAIO errors, reading and writing. The errno value states there was an address error. Well after going down to 100000 buffers no errors seemed to appear. After 4 days, in which the customer worked without any complaints, I checked the online.log and there where again lots of lines about KAIO errors. Additionaly I found an assertion error, with the hint to do a oncheck -cDBI. I did the oncheck during the night and some corruptedindexes where fixed. We didn't change anything on the OS, except activating the 2 additional CPU's. We changed the Number of CPUVP's to 3 instead of 2 and added the BUFFERS mentioned above. The kernelparmeters for shared memory and semaphores are set according to the MACHNOTES in the documentation. Since IDS is not complaining anything about not getting shared memory, I can't quite figure out what's going on here. I'm not sure the corrupted Indexes are a result of the KAIO errors, so I am considering falling back to IDS-AIO. Does anybody have a idea (I'm not sure the suggested SHMMAX value of 409600000, which resembles ~400Mb is the problem, but why this could cause address errors in the KAIO routines instead of an error in IDS-Memory allocation?). Thanks for any help Walter

We faced unix errors when we first enabled KAIO. We are got rid of them with the following kernel parameters: NAIOPROC 100 NAIOREQ 5000 NAIOBUF 5000 NAIOHBUF 1000 NAIOREQPP 5000 SDSKOUT 256 You can check what you need with aioinfo I am told there is a patch for 5.0.4 concerning aio (we are on 5.0.5). Bashar Chalabi CTL, London