• [^] # Re: Self-Certifying File System

    Posté par . En réponse à la dépêche Self-Certifying File System. Évalué à 1.

    mes notes a moi :


    IBM afs v 3.6 || openAfs || Arla Project
    ----------------------------------------
    Andrew FileSytem initially developped at Carnegie Mellow University ( CMU ),
    then by TransArc, then IBM.
    IBM forked the developpement tree in 2000 to give birth to OpenAfs, open-source
    , free and widely used (IPL licence).
    Recently, the ArlA project implements Afs Protocol under GPL licence.
    At this time the client-side is supported, the server-side is undergoing
    heavy developpement.

    * AFS supports a maximum file size of 2 GB.
    * RPC based.
    * AFS supports a maximum volume size of 8 GB. In AFS version 3.5 and earlier,
    the limit is 2 GB. There is no limit on partition size other than the one
    imposed by the operating system.
    * less CPU usage than NFS 2-4 times less. definetly faster. great scalability.
    * RedHat 6.x & kernel 2.2.x, likely 2.4.x as well .
    * kerberos-like or kerberos-based security.
    * client caching , server replication
    * 'encrypted' file system & authentification...
    * a fileserver can be an authserver..
    * used in many Universities ... designed to support 5,000-10,000 clients.

    IBM:
    * NFS/AFS translator to keep volumes accessible by nono-afs client.
    * underliying rcp , rsh ?
    http://oss.software.ibm.com/developerworks/opensource/afs/docs/html(...)
    * rsh , inetd rcp, etc... remplacement...
    * tons of documentation

    * Arla is a free implementation . client-side, working on server-side.

    * Andrew II fs.

    * Solaris client&server
    * Linux Client&server


    Coda
    ----
    Coda is a project also managed in CMU. it's aim is to be "better" than Afs
    in disconnected and weakly connected mode.

    * from Afs2.
    * RPC based.
    * no compagny support ..
    * security -> weak build-in or kerberos patch. weak == XOR scrambling, but
    the challenge protocol is secure.
    * namespace, volume-sharing, not directory.
    * Coda is a forked of version of AFS that support disconnected and weakly
    connected mode better then AFS.

    client point of view :
    * disconnected operations , caching ...
    * open() means copy() - based on file replication/caching.
    * small 10-200 Mo caching recommended. It seems that coda's users have
    larger cache area.
    * file to cache selectionnable ( hoarding ).
    * kernel support needed . very little patch, user-land application ( Venus ).
    * on update conflicts, user might need to resolve it manually..

    server pov:
    * replication
    * consistency & transactions

    * DFS sysadm seems to prefers Coda to Afs.
    * Coda seems not to be scalable :
    The documentation says the RVM metadata needs to be 4% of the total
    shared size and it needs to be backed by virtual memory for that same
    quantity.

    * Linux client&server
    * Solaris client , no server


    Ficus, Rumor & ROAR
    -------------------
    * designed at UCLA for large scale DFS.
    * peer-to-peer structure.
    * optimistic consistency approach.
    * intelligent resolvation of update conflicts.
    * Rumor user-space implementation is beta stage.
    * intelligent hoarding.
    * Really accurate for mobile and disconnected DFS.

    Sistina GFS 5.1
    ---------------
    * used for cluster's filesystem on fast LAN.
    * not useable on WAN networks.

    DAFS ( www.dafscollaborative.org )
    ----
    * file sharing on SAN . Not for WAN .

    Sprite fs, part of SpriteOS
    ---------------------------
    * no caching on write-shared files.
    * spritely NFS ?
    * less CPU-eater than NFS.
    * superseeded by afs.

    xFS - A Wide Area Mass Storage File System
    ------------------------------------------
    * wwwos93.ps
    * multi hierarchical & caching
    * -> IBM XFS ? no network issue and LAN-applicated.

    Amoeba
    -------
    * Amoeba is a DOS, so there is a DFS in it..
    * micro-kernel and stuff..

    Odyssey
    -------
    * application-aware.
    * need the application to be compliant.


    SFS @ sfs.net
    ---
    * secure, encrypted...
    * basicaly , it's a encrypted NFS.
    * relies on nfsv3.
    * easy to install.
    * a lack of pam modules ?

    SFS @ http://www.cs.auckland.ac.nz/~pgut001/sfs/(...)
    ---
    * secure, encrypted...
    * windows & Dos

    Lustre
    ---------
    * Another LAN-cluster dfs.


    LBFS - A Low-bandwidth Network File System
    --------------------------------------------
    * Whole file Caching
    * NFS-like protocol. Over-NFS implementation.
    * Chunk SHA-1 calculation and comparaison.
    * Very _LOW_ bandwith utilisation.
    * SFS encryption support
    * Not for disconnected operations.
    * High disk load.
    * Need a Berkeley DB.
    * Probably high CPU load .
    * Less bandwith use than NFS,AFS...
    * Faster execution time.
    * Designed for Wan access.
    * 2 implementations
    a) with the xfs-arla client - caching, chunking but no authentification
    b) with the SFS client - authentification but no chunking,
    -small- freebsd nfs kernel patch, no linux patch .

    InterMezzo
    --------------
    * pretty much like Coda.
    * AFS -> COda -> Intermezzo
    * Aiming disconnected ops.
    * GPL
    * Module-Compilated in Redhat 7.3
    * More efficient than Coda is.

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