[Stgt-devel] Tuning iSER for performance

Bart Van Assche bart.vanassche
Mon Feb 11 08:33:59 CET 2008

On Feb 11, 2008 6:59 AM, Erez Zilber <erezz at voltaire.com> wrote:
> I'm not talking about running the initiator & the target from the same
> machine. What I said is that if you're running the initiator on machine
> 'A' and the target on machine 'B', I see the following behavior:
>     * running sgp_dd directly from the target machine - 400 MB/sec
>       (which is the throughput of the LUN)
>     * running sgp_dd from the initiator on the same LUN - 240 MB/sec
> If you get better numbers, I'm interested to know if you're using the
> default config or anything else.

The results I obtained with STGT over iSER on an SDR network are as
follows (direct I/O with  xdd):
* 7.4 MB/s for reading data in blocks of 512 bytes and 8.9 MB/s for writing.
* 363 MB/s for reading data in blocks of 65536 bytes and 346 MB/s for writing.
* 890 MB/s for reading data in blocks of 10 MB and 900 MB/s for writing.

Please keep in mind that when running a filesystem on top of iSCSI
that all transfers happen in units of 64 KB or less.

Bart Van Assche.

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