mount Ramdisk (not initrd) at boot?

[pactoo]

Is it possible, to create and mount a ramdisk at boot time? Let's say, I would like /tmp to be a ramdisk - not tmpfs - so I need to set the size of the ramdisk somewhere and get it formatted it. Are there some scripts or config files where this could be done? Like similar to configure/setting up a crypted swap?

[BradN]

I strongly recommend considering a loopback file instead of a ramdisk unless your main aim is to eliminate hard drive I/O completely (for energy or wear reduction, not performance reasons). I believe filesystem is still going to spend time doing cache/buffer processing anyway (not 100% sure though) unless you go with tmpfs or something like that, so you might as well make it disk backed if you can. This is easily set up right in fstab after you've created the loopback file.

You won't find a config option made for this, you'll have to write your own init script, modify one that runs early enough, or if you don't need it ready until login, make it part of local.start.