Ø Is that documented anywhere? Any reason why performance will suffer? I can understand on normal and high redundancy, but I cant figure out what difference it would make on external redundancy. Yes it is. ASM stripes over all disks in the diskgroup, so any different sizes prevents it from doing that evenly. Andy -- The Wellcome Trust Sanger Institute is operated by Genome Research Limited, a charity registered in England with number 1021457 and a company registered in England with number 2742969, whose registered office is 215 Euston Road, London, NW1 2BE.