I created a software raid 5 disk using: mdadm -C /dev/md2 -l5 -n4 /dev/sd[i-l] at the same time I'm using dstat to see io-activity: dstat -c -d -D total,sda1,md2,sdi,sdj,sdk,sdl -l -m -n and notice that disks sd[i-k] are all read from and sdl is written to. Now, I do understand that raid5 has to be configured, but it takes a really long time and all disks are clean & formatted (using xfs) so I figure there might be some kind of shortcut to skip (unnecessary? ) checking.. Is it? The creation is part of a time-critical nightly batch-process (run on amazon ec2) so it's not a one-time thing. Thanks, Geert-Jan