[OmniOS-discuss] NBD on OmniOS

[Michael Mounteney]

On Tue, 27 Aug 2013 09:59:59 +0200
Jim Klimov <jimklimov at cos.ru> wrote:

> Did you analyze why it is slow?

Not why, but how much.  I ran bonnie and it produced these figures, for

1.  Standard NFS root.
2.  NFS root with zfs set sync=disabled
3.  iSCSI

Switch to a fixed-pitch font to read this properly:
<t>
              -------Sequential Output--------   ---Sequential Input--  --Random--
              -Per Char- --Block--- -Rewrite--  -Per Char-  --Block---  --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  K/sec %CPU    /sec %CPU
NFS      2000  9100 88.8  9495  3.7  4664  7.0  9485 83.8  51780 31.6   642.7 10.1
NFSasync 2000  9452 89.9 16085  7.5 12697 24.6  9505 83.7  85361 34.8  5336.4 69.0
iSCSI    2000  9885 97.0 15523 13.5 16650 16.9 11623 99.1 114326 46.4 13092.1 99.5
</t>

so iSCSI is faster, but it also sucks CPU, which is not surprising as
it is doing the full filesystem thing rather than working at filename
level and handing off work to the server.  So I reckon that iSCSI
won't be faster as a root filesystem, when the CPU is doing other
stuff associated with booting and running.  These tests were run
while the machine was quiescent.

Michael.