[446] in Info-AFS_Redistribution
Re: AFS and NeXTs
daemon@ATHENA.MIT.EDU (Wallace Colyer)
Mon Nov 18 12:01:22 1991
Date: Mon, 18 Nov 1991 11:15:58 -0500 (EST)
From: Wallace Colyer <wally+@andrew.cmu.edu>
To: Info-AFS@transarc.com, Craig_Everhart@transarc.com
Cc: "Michael T. Stolarchuk" <mts@terminator.cc.umich.edu>,
In-Reply-To: <kd9xP_z0BwwOABCV4H@transarc.com>
This problem is most obvious in the case of cross cell mount points, but
it is also a problem with mount points in general. Our next machines
beat up the vldb servers and perform poorly on directories like:
/afs/andrew.cmu.edu/usr
Things are better because it only stats what is shown, but it is still
unfair to do this and scrolling can be miserable.
If you allow the sticky bit to return different information on a stat
you have to have some way of setting the sticky bit as well since any
operation on the mount point will currently only change the directory.
Stats are still expensive no matter what you do at this level. If I
don't care about the little arrow in the lower levels of a browser
window why should I pay for them. For example, if the level below me is
a bunch of symlinks pointing to mount points or directories which can be
3 or 4 levels away they I have to pay for fetching each symlink, and the
intervening directories. This is a cost I would rather not pay for.
This can happen even if what is being fetched is not a mount point.
The cost is even too much if the level bellow is jut a bunch of
directories.
So I return to an option that allows me to specify that stats are
expensive and reduce their frequency. If indeed 10% of the AFS installed
base is NeXT (which I find very hard to believe) I would think that NeXT
would like to work well with AFS. Currently, it still has major
deficiencies which are both bothersome to the user and unfriendly to the
servers.
I don't argue that putting something into AFS which makes these stats
less expensive would be an atractive solution, but allowing machines to
perform poorly because of an idealistic stand looks like a very poor
attitude to the customers.
-Wallace
