chris_good@webtop.com writes:
Just don't use the mix of 18 and 36Gb drive in the SAME volume. That is bad. I don't see why you can't have different disk shelves of same drives, ie. a shelf of 18s and another shelf of 36s, attached to an F720. We have this config on an F760.
NO, what you must not do is mix disk sizes in a *raid group*. Its fine to mix in a volume as long as they're in different raidgroups. I think the confusion arises as many peoples volumes don't span raidgroups. Another thing I would advise against is mixing sizes in a shelf.
Seperating different disc sizes into different RAID groups avoids various sorts of disc space wastage in the short term. But it doesn't alter the fact that if you have a mixture of disc sizes within a volume, you are stuck with that state for as long as the volume exists: you can never expand a data plane to effectively use a larger disc.
Chris Thompson University of Cambridge Computing Service, Email: cet1@ucs.cam.ac.uk New Museums Site, Cambridge CB2 3QG, Phone: +44 1223 334715 United Kingdom.