I've been working with people who anticipate that big flash that looks like ram will be available mid/end of the decade. By big, I mean big as your disk. By RAM, yep, I mean RAM. Reboot, it's all still there.
Needless to say, this changes things a bit. I also noticed the venti stats: many of the ventis I've seen don't have more than about 30G used. 30G? I can get a 1U with 512G for 18K nowadays. 1TB for 36K. Finally, it's always bothered me that to most people, Plan 9 file systems are a black box. Plan9ports has a very nice "devnull" venti that seemed like it could be used for a real system. I thought it might be fun to have a very simple venti that uses an mmapped backing store and a common hash library (posix hash, available everywhere) as a demo and to maybe get people wanting to hack in this area. So on the long boring flight to Spain, I threw one together. So, see it here: http://pastebin.com/47aC2XGv To use, just drop into src/cmd/venti, fix mkfile, mk all to make an arena, the usual dd from /dev/zero To run, you can, e.g.: ./o.devram -s 2 -a 'tcp!*!6666' /tmp/arenas the '2' here means two GB. To grow the arena, tack zeros onto the end, and restart. To test, used randtest. Or vac. Or whatever. I've set -s to 32 and had a 32GB venti. Sync is a no-op; it always syncs on each write. Performance: well, you try it :-) Mistakes and bugs and things to be done better? Of course! Lucho pointed out some to me already. You can find more. Hack away! And, there's going to be a better version soon. I think. But the more versions floating around, the better. have fun. ron
