users as blobs

Matthew Dillon dillon at apollo.backplane.com
Mon Sep 4 11:20:49 PDT 2006



:Am 04.09.2006 um 00:16 schrieb walt:
:
:> Are you thinking about, say, pointers to my real blob which exists
:> on one physical server, or actually migrating blob->walt to anywhere
:> I'm actually needed?  (Most likely to unplug the sink or the toilet.)

    Ultimately this means having your real blob 'somewhere out there on
    the internet', encrypted and available for your use.  Anyone follow
    'Ghost in the Shell' Anime?.  this is almost exactly the
    'external memories' abstraction they refer to.

    You want to be able to have some ephermal 'blob' containing your personal
    data which might span hundreds of gigabytes.  You want to access this
    blob from anywhere... home, laptop while on the road, etc, so it must
    be accessible over the internet.  You want any given machine to be
    fully coherent with changes made from any other machine and you do not
    want to have to recopy those hundreds of gigabytes every time you 
    change machines... or at all, really.  

    This sounds like a job for a cache cohereny management system.  You
    want the local storage on each machine (potentially also hundreds of
    gigabytes per box) to act as a persisent hot cache so access to your
    data operates at local HD speeds most of th time.  It is somewhat of
    an extension to the current DragonFly plan for cache coherency, but
    we do already have an abstraction in the system called FSMID that would
    make it possible to keep long-term (persisent) data sets coherent.  So
    filesystems with FSMID could be used for long-term coherency while
    CCMS (the cache coherency management system currently being contemplated)
    could be used to handle short-term coherency.  A unionfs-like layering
    could be used to maintain the visibility abstraction (of seeing all your
    data all the time regardless of what has actually been cached on any
    given box).

    I think it is quite doable once these other mechanisms have been
    fleshed out.

						-Matt






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