Terrible NFS performance under 9.2-RELEASE?

[J David]

On Fri, Jan 31, 2014 at 6:16 PM, Rick Macklem <rmacklem at uoguelph.ca> wrote:
> You can certainly try "-o rsize=61440,wsize=61440" (assuming a 4K page size)
> for the mount, if you'd like.

This has previously been tested with all 4k steps between 16k and 32k.
 All of them perform worse than

With 61440, NFS fails outright on the random read test:

$ iozone -e -I -s 1g -r 4k -i 0 -i 2

Iozone: Performance Test of File I/O

        Version $Revision: 3.420 $

Compiled for 64 bit mode.

Build: freebsd

[...]

Include fsync in write timing

O_DIRECT feature enabled

File size set to 1048576 KB

Record Size 4 KB

Command line used: iozone -e -I -s 1g -r 4k -i 0 -i 2

Output is in Kbytes/sec

Time Resolution = 0.000005 seconds.

Processor cache size set to 1024 Kbytes.

Processor cache line size set to 32 bytes.

File stride size set to 17 * record size.

                                                            random
random    bkwd   record   stride

              KB  reclen   write rewrite    read    reread    read
write    read  rewrite     read   fwrite frewrite   fread  freread

         1048576       4   24688   23891

Error reading block at 1073729536

read: Bad file descriptor


Upon using the -w option, which leaves the file intact on exit, it's
possible to see that it's not even 1gig in length:

$ ls -aln iozone.tmp

-rw-r-----  1 1000  0  1073709056 Feb  1 01:18 iozone.tmp


It's 32k short, which is a pretty surprising result.

Thanks!