Re: Raw vs. cooked

Tom Smith wrote: > > Let's put this issue to rest -- or maybe not: > > Is IDS's performance better using raw diskspace or the Unix filesystems, > aka "cooked files?" A Sun field sales/system engineer recently told me > that Sun's filesystems are so sophisticated now that the performance is > identical. Another system developer told me that he had benchmarked the > two, and had seen a slight disadvantage to using Informix on Solaris > with raw space. However, he said a different Unix flavor had abysmal > cooked file performance compared to raw. > > What have others found? Does Informix have any published (recent) > benchmarks that address this question? I agree that the raw disks _should_ be faster, but it also depends greatly on the engine release, and the engine version. The latest versions are performing faster simply due to some profoundly simple fixes in how LRUs are managed, if my memory serves me correctly. 8.x engines are going to be profoundly faster simply because of the higher release number. Just kidding! :-) Seriously there are so many variables I would be very wary of anything claiming exceptional performance with cooked files being faster than raw disks. The bottom line for you is to use accepted practice on your implementation so that you can share in the pain and glory of other shops. By the way I've found out recently in talking with the ATG that there are some other foundations crumbling, notably the idea of "one dbspace per disk". Performance on 8.x is supposedly faster on some platforms where instead of putting dbspaces on separate drives you go with lots of spaces offset into one drive. Don't try this without adult supervision, bad offsetting will be messy. :-) You won't be able to do this with cooked files, but as a feature of cooked files I guess the size of the cooked-dbspace by itself makes the distribution interesting in terms of drive usage. The other interesting thing to raw vs. cooked is that in the upcoming release of 8.3, you can change the page size from 2K to 16K, in 2K increments. This is pretty cool, and I would imagine applies more to a raw disk world than cooked files. It might make the whole equation new. I cannot imagine the competition doing well if Informix marketing gets on the stick and actually sells their engines. 8.3 has just gone into beta, and it will be interesting to see what shakes out. Thanks, Tim - - -- --- Tim Schaefer ---- tschaefe@mindspring.com --- http://www.inxutil.com -- -