Journal Systemes de fichiers distribues

faisez gaffe, c'est <blink>gros</blink>

d'ailleurs on peut pas faire une intro de journal et un corps de journal separe ?

Desole c'est en anglais .. et c'est de la prise de note ...

There are many DFS in the wild but just a few are adapted .
Afs and Coda are based on volume-sharing , which is a bit different than
usual directory exports.

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/AdminGd/auagd002.htm#ToC_97
* 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.