Re: IDS 10.00.HC5 Performance problem on HPUX 11.11

Deldongo wrote: > Dear, > > So far I beleived that raw device offers far better performance over > cooked files. > > recently, I had the opportunity to install 2 instances on the same > machine (same onconfig file). I assume you have two onconfig files with different root dbspace, different servernumber, different servername and serveraliases. > > The only differences between the two instances it that the 1st one is > build over raw devices when the second one is build over cooked files. > > On the fist instance I activated KIO (KAIOON=1, /dev/async is present > asyncdriver is present in the kernel). > > I then ran a big dbimport: > > it took 1h20 minutes on the first instance (raw device KIO based) > it tooked 1h00 on the second one (cooked files based) > > Anyone has an explanation ? Did I missed something in the KAIO > configuration ? Isn't it necessary to use raw devices anymore ? When using cooked devices the file system will allocate buffers, so your total buffer pool is IDS buffer + file buffers. When you use raw devices you don't have file buffers, so typically you will have more memory available for the IDS buffer. If you can find out the size of file buffers, you should increase the IDS buffer with this amount for the 'raw device' configuration to make it more comparable. Usually it's preferably to avoid the double buffering, but if you have reached the maximum size for what you can allocate for the IDS buffer and still have available memory, you might gain from the extra buffers the file system can provide. > > Thanks for your help. > > Deldongo >