[OpenAFS] Is OpenAFS for me?

Juha Jäykkä juhaj@iki.fi
Tue, 07 Mar 2006 18:25:33 +0200

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> > 2) Expandable. Can I add another 400-500GB drive to a new computer and
> > add it to an existing OpenAFS volume?
>    No.  Not without some sort of layer below AFS.  All AFS volumes
>    live in an existing filesystem on the server.  If the server has
>    the capability to grow a filesystem unbeknownst to AFS that
>    might work (but I personally am not aware of any such thing).

Having spent the last few months explaining volumes to people who are used
to the thought that filesystem equals partition, I am afraid there is a
possibility of misunderstanding here.

Karl: did you intentionally ask about volumes or did you mean "the corner
of universe where my files reside on an AFS"? You can add stuff to your
AFS very easily with no limits what so ever. You *cannot* add new drives
to an existing volume, but I do not think you would ever even want to.

AFS gives you volumes precisely for the reason that you can keep your
"units of administration" small. If you create a 100 1 GB volumes on a 100
GB filesystem and it fills up, you can just add another filesystem on ANY
server in the cell, make the new filesystem ANY size you wish and move one
of more of those 1 GB volumes over to the new server. Suppose you move 10
of the volumes to a new 1 TB filesystem. Now the old server has 10 GB free
space for the remaining 90 volumes to consume and the new filesystem has
990 GB free space for those 10 volumes to grow into. You can always "add
space to a volume" by moving the volume to a new filesystem which has more
free space than the old one. There should not be a need to add space in
any other way.=20

By the way, the users will not notice that you moved the volume to a new
server, you can move it at will and the users do not even have to log off.


		| Juha J=E4ykk=E4, juolja@utu.fi			|
		| home: http://www.utu.fi/~juolja/		|

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