[598] in Info-AFS_Redistribution
Re: NFS vs. AFS builds
daemon@ATHENA.MIT.EDU (Ed Gould)
Tue Feb 11 21:45:38 1992
To: dstokes@sunlight.austin.ibm.com
Cc: info-afs@transarc.com, carl@shade.austin.ibm.com
In-Reply-To: Your message of "Tue, 11 Feb 92 14:04:25 CST."
Date: Tue, 11 Feb 92 17:04:33 -0800
From: Ed Gould <ed@pa.dec.com>
>
>
> Nobody here in Austin has come up with a good answer for these questions,
> so I thought I post this to the experts.
>> AFS is slower to do builds. A lot slower. Why is this? Why doesn't
>> a 200MB cache fix this? Why is the 2nd build no faster than the first?
>> The following is a comparison of AFS vs. NFS builds*. The net result
>> here is that AFS took twice as NFS
Tha answer is almost certainly that AFS synchronizes its writes to the server at
file close time, waiting for the entire file to be written to the server at that
time. NFS is synchronous to the server on a block-by-block basis, hence it
doesn't wait for the writes to complete at any point - blocks are flushed to the
server as required by the client buffer cache. This typically happens in parallel
to other activity.
Ed
