What is the recommended way of setting a default IO scheduler on Linux?

I would like deadline to be the default IO scheduler for my system, and I don't want to lose that config when I reboot. What is the proper way of doing that? (I'm using Debian) Some hints: - have a startup script doing echo deadline >| /sys/block/sda/queue/scheduler, - use the kernel parameter elevator=deadline on GRUB startup config, - use a udev rule like SUBSYSTEM=="block", ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/scheduler}="deadline", - etc. What is the "preferred" solution? **EDIT:** can I have a configuration which set the iosched to deadline only for drives present at bootup, but not for subsequent hot-plugged drives (like USB keys)?