[542] in Info-AFS_Redistribution
Re: some questions about using AFS to share core OS files
daemon@ATHENA.MIT.EDU (Lyle_Seaman@transarc.com)
Fri Jan 17 12:43:44 1992
Date: Fri, 17 Jan 1992 10:32:17 -0500 (EST)
From: Lyle_Seaman@transarc.com
To: Info-AFS@transarc.com, John Hascall <john@iastate.edu>
In-Reply-To: <9201162142.AA03657@iastate.edu>
John Hascall (Project Vincent) <john@iastate.edu> writes:
> All this talk of problems with multiple user's on AFS served systems is
> somewhat troubling (while most of our workstations have either a single
> user or just a few users at once, our "telnet" machine (a DS5000) generally
> has dozens of users). I, for one, would appreciate someone from Transarc
> explaining what this is all about.
AFS-3 was originally designed for single or dual-user clients. As
such, there were a number of design decisions made that were adequate
for that environment, but were sub-optimal for clients with (eg)
dozens of users. These shortcomings include relative coarseness of
locks on key data structures, locks being held longer than absolutely
necessary, and a cache of access bits that only held access rights for
two users at a time (plus system:anyuser).
These shortcomings were manifested as reduced performance.
Most of these cited shortcomings have been fixed for AFS 3.2. There
is still one lock that could be managed better, but we simply couldn't
get to it in time for 3.2; I hope it will be improved in a subsequent
release.
FYI, these particular issues were addressed from the outset in the
design of AFS-4.
Lyle Transarc 707 Grant Street
412 338 4474 The Gulf Tower Pittsburgh 15219
