With SunOS you can use the format command to slice a disk up any way that you want. Ideally, you should create a slice that belongs to Informix alone and then use an offset of zero since Informix can use the entire slice.

If you couldn't define your own slices, you might need, as one example, to have one area serve as both swap and an informix chunk. If the area was, say, 2 gigs, you might define a 1 gig swap area. Then informix would use the same area with an offset of 1 gig.

The only problem you might encounter is the disk label itself. You don't want to overwrite that. If your slice 1 starts on cylinder zero, you must tell informix to skip the first sector so that you don't clobber the label. I would move slice 1 off of cylinder zero and still use an Informix offset of zero. If you really must start the slice on cylinder zero, then use an offset of 512 to preserve the label.