Re: Help with Dbspaces & Chunks?

Andrew Burt writes: >Not that this affects you, but note that there is an (undocumented, as far >I saw) limit on chunks being 2Gb max. With large drives at and above this >size, esp. with RAID drives & other multi-disk tricks, I found this limit >rather annoying (mainly since it wasn't clearly documented, if indeed it's >written down anywhere at all). This is true, but do consider that this is a Unix limitation and not an Informix one, for the most part. Unix limits the offset in an lseek() call to the maximum value in an unsigned long. Since this puts you at 2 Gb, that is the most you could seek in one operation. Since OnLine attempts to do all seeks as a single operation for performance reasons, you wind up with the 2Gb limit. Also note that this limit cannot be circumvented by creating multiple chunks in a single large device because we add the chunk offset and the location withing the chunk together to form the lseek argument. Thus if you have a partition > 2Gb, you can only use the initial 2Gb. The best solution is to partition those large drives into pieces 2Gb or less in size. It's probably not documented anywhere, mostly because we didn't realize it was going to be a problem until after the docs were out. I believe it will be included in the 6.0 documentation. Dave -- Disclaimer: These opinions are not those of Informix Software, Inc. ************************************************************************** "I look back with some satisfaction on what an idiot I was when I was 25, but when I do that, I'm assuming I'm no longer an idiot." - Andy Rooney