> I think I could understand what you want. > But it is very hard (almost impossible) to know whether the "write" will > fit in ramdisk or not before the actual write. ENOSPC error will surely > happen. > You may want aufs to do, > - /au = /ram + /hdd > - user issues write(2) to /aufs/fileA > - fileA exists /ram and aufs writes to /ram/fileA. > - /ram becomes full and ENOSPC occurs. > - aufs copy-down (or move-down) /ram/fileA to /hdd/fileA and writes the > originally requested data to /hdd/fileA. > > Currently aufs has no such feature.
Exactly! In the meanwhile I've managed to make it work with FUSE-based mhddfs, but because of the insane FUSE overhead it gives pitiful results. If you implement this in AuFS, you'll will finally make fast and reliable temporary filesystems possible. I hope you will! Cheers, -- Sergey "Shnatsel" Davidoff ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1
