On Thursday 12 March 2009, Michael Keulkeul wrote: > Hi all, > > Would it be possible to have a dedicated device for fast syncronious > transactions, and latter flush to slower storage with tux3, or is this hard > because of the design ? > Sort-of copy the ZIL scheme of ZFS, and be able to recover all writes after > a failover or a power loss. > > Thanks in advance for your answers ! > > Michael B.
Hi Michael, I expect Tux3 to be pretty fast for synchronous writes even without a scheme like ZIL. But if it were to be done, I would think a generic virtual block device that implements a heirarchical cache would make more sense than doing something special in the filesystem. In general, I would like to view most of this "accelerate disk with a small amount of expensive persistent storage" ideas as logical volume manager problems. Unsolved ones, to be sure, but no actual reason for that. As a volume manager solution, we could map part of the volume to fast disk and most of the volume to normal, slow disk. Then we always allocate new writes into the fast disk area, and migrate those blocks off somewhere else later (yes, Tux3 will have block migration). A good Master's thesis or two in there for someone. Regards, Daniel _______________________________________________ Tux3 mailing list Tux3@tux3.org http://mailman.tux3.org/cgi-bin/mailman/listinfo/tux3