AFS

Barry Shein bzs at bu-cs.BU.EDU
Fri Jun 9 10:50:03 AEST 1989


William Sommerfeld responds to Melinda Shore
>In article <881 at mtxinu.UUCP> shore at mtxinu.COM (Melinda Shore) writes:
>
>   Allow me to add a few items to the bad things list:
>
>Allow me to rebut a few of them.

And then proceeds to agree with every one of her points except two
(and even those seem hedged, like he wished Melinda had worded it
differently rather than a "rebuttal".)

What was the point of this, to say there was some rationale for all
these differences she pointed out? Then why the lead-in that you were
going to rebut? False advertising.

>   1) The [protection] semantics really are different from Unix
>     filesystem semantics.
>
>The use of access control lists is necessary in large-scale
>environments.

A rebuttal?

>   2)  Directories, which you and I consider to be files, aren't treated as
>	   files by AFS.  *No* caching, which means that you can ls until the
>	   cows come home but the 80th time is not going to be any faster than
>	   the first.
>
>Please check your facts; last I looked, they're cached just like files.
>A significant part of the hair in the AFS client is involved with
>keeping the local copy of a directory in synch with the master copy
>when directory operations are done.

Ok, we'll give you that one. Are you sure this isn't a newer version?

>   3)  Performance.  The whole file is copied over at access time, which
>	   speeds up future file accesses but can turn "grep string *" into a
>	   fairly unpleasant experience.
>
>Yes, but the user process doing the "grep" sees the bits as soon as
>they're available, and doesn't have to wait for them to be written to
>the cache.

Obviously someone here is wrong.

>   4)  Disk usage.  Because entire files are copied over it can be something
>	   of a disk burner.
>
>True; you want a large enough cache that the "working set" of files

Not a rebuttal.

>   5)  Administration is somewhat (!) complex.  
>
>Agreed, but managing 10 AFS servers is only slightly harder than

Not a rebuttal.
-- 
	-Barry Shein

Software Tool & Die, Purveyors to the Trade
1330 Beacon Street, Brookline, MA 02146, (617) 739-0202



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