Glossary

AFS-Glossary

D-E

G-J

N-O

Q

S

W-Z

A

  • AccessControl
    ACLs are enforced on the directory-level. Within one directory all files have the same protection.
    Available Rights :

    • a - administer : change ACL in this directory

    • d - delete : delete a file in a directory

    • i - insert : insert a file in this directory

    • k - lock : lock files in this directory

    • l - lookup : change into this directory, see all filenames

    • r - read : read files

    • w - write : write to files

    Notes :

    • To create new files both i+w rights are necessary.

    • In order to see files in the windows explorer or to do a ls -l on unix, both r+l rights are required.

B

  • bosserver :
    server-program which takes care that the other server-programs are running and restarts those in case of a failure

  • bos <unix-command> :
    client program to query and manipulate the bosserver.

C

  • Cell
    a Cell is an adminstrative unit within AFS. All servers and clients belong to one cell. The name of the cell is usually the second directory of the namespace /afs/<cellname>/…, e.g. here it is /afs/ipp-garching.mpg.de/

  • CellAlias
    abbreviation of the cellname in the namespace. Here it is e.g. /afs/ipp/ for /afs/ipp-garching.mpg.de/

  • Client
    sometimes also referred to as cache-manager.
    Program which provides access to AFS. Listens on port 7001/udp.

  • Client-cache
    filespace in memory or disc of the client to store data locally. Thus, data do not have to be retrieved form the server everytime the client accesses them.

  • Callback
    Mechanism of the fileserver to tell the client, that some files in its cache have been changed by a different client and must be discarded from the client-cache.

D

E

F

  • fs <unix-command> :
    client program to query the fileserver. Gives various information about the files and directory a client is using.

  • fileserver :
    server-program which actually serves the file-data. Controlled by the bosserver. Listens on port 7000/udp

  • firewall settings client :
    following rules should be applied :
    outgoing connections to afs-servers, ports 7000-7011/udp
    incoming connections from afs-fileservers on port 7000/udp

G

H

I

J

K

  • Kerberos5 network security framework.
    On Unix there are (at least) two free implementations : heimdal and MIT.

L

M

  • Mountpoint
    point in the namespace to a particular volume. It is implemented as a symbolic link. A mountpoint may point to a RW or a RO Volume.
    Unix-commands: fs listmount <path>, fs mkmount <path>, fs rmmount <path>

N

O

P

  • Protection Server :
    Server-program which deals with users and groups within AFS. Listens on port 7002/udp.

  • PRDB :
    PRotectionDataBase, used by the Protection server

  • pts <unix-command> :
    used to query the protection server in order to create/manipulate groups, users and other things with connected to authorization.

Q

R

  • RX <network-Protocol> :
    used by AFS for the data connections between client and server, and server and server

  • rxdebug <unix-command> :
    client program to query the afs-servers on the network level, prints various information about the peer queried.

S

T

  • (Kerberos-) Ticket :
    Ticket (as for a ski-lift) identifying you as yourself in a network structure. Used for creating AFS-tokens. Generally known as credential.

  • (AFS-) Token :
    Credential which identifies you as a user within AFS. Without a token you will not have write access to AFS. The rights you have within AFS depend on your token and the ACL.

U

  • ubik :
    network protocol to synchronize databases on different servers. Used by AFS for the VLDB, PRDB.

  • udebug <unix-command> :
    client-program to query servers running the ubik protocol.

V

  • Volume
    Segment of the file-space on a fileserver. Comparable to a partition on a harddisk or a directory tree.
    Volumes can be moved between servers without almost no interuption of the accessibility.
    Types of Volumes: Readwrite (RW),Readonly(RO),Backup(BK)

  • Volumegroup
    group of corresponding RW, RO and BK Volumes. There are only 7 members in a single volumegroup allowed.

  • Volserver (Volume-Server):
    Server-program which deals with volume operations (like release). Controlled by bosserver. Listens on port 7005/udp

  • VLServer (VolumeLocation-Server) :
    Server-program which handles the volumelocation database. Controlled by bosserver. Listens on port 7003/udp

  • VLDB :
    Volume Location DataBase. Contains information which volume is on what server.

  • vos <unix-command> :
    client-program to query the volserver and the vlserver.

W

X

Y

Z