Why is NFSv4 so slow?

[Rick C. Petty]

On Sun, Jun 27, 2010 at 08:04:28PM -0400, Rick Macklem wrote:
> 
> Weird, I don't see that here. The only thing I can think of is that the
> experimental client/server will try to do I/O at the size of MAXBSIZE
> by default, which might be causing a burst of traffic your net interface
> can't keep up with. (This can be turned down to 32K via the
> rsize=32768,wsize=32768 mount options. I found this necessary to avoid
> abissmal performance on some Macs for the Mac OS X port.)

I just ran into the speed problem again after remounting.  This time
I tried to do a "make buildworld" and make got stuck on [newnfsreq] for
ten minutes, with no other filesystem activity on either client or server.

The file system corruption is still pretty bad.  I can no longer build any
ports on one machine, because after the port is extracted, the config.sub
files are being filled with all zeros.  It took me awhile to track this
down while trying to build devel/libtool22:

+ ac_build_alias=amd64-portbld-freebsd8.1
+ test xamd64-portbld-freebsd8.1 = x
+ test xamd64-portbld-freebsd8.1 = x
+ /bin/sh libltdl/config/config.sub amd64-portbld-freebsd8.1
+ ac_cv_build=''
+ printf '%s\n' 'configure:4596: result: '
+ printf '%s\n' ''

+ as_fn_error 'invalid value of canonical build' 4600 5
+ as_status=0
+ test 0 -eq 0
+ as_status=1
+ test 5

And although my work dir is on local disk,

% hd work/libtool-2.2.6b/libltdl/config/config.sub:

00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
|................|
*
00007660

Again, my ports tree is mounted as FSType nfs with option nfsv4.
FreeBSD/amd64 8.1-PRERELEASE r208408M GENERIC kernel.

-- Rick C. Petty