[DRBD-user] Sockets Direct Protocol (SDP)

Lars Ellenberg lars.ellenberg at linbit.com
Sat Oct 27 10:48:34 CEST 2012

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Thu, Oct 25, 2012 at 11:38:42AM +0200, Florian Haas wrote:
> On Wed, Oct 24, 2012 at 2:28 PM, Matthew Goulding <matt at dnuk.com> wrote:
> > Hi All!,
> >
> > I have been looking into to using Infiniband with SDP.
> >
> > Though from what i read SDP is now deprecated and the "ib_sdp" module is no
> > longer part of OFED or the kernel.
> >
> > Ref:
> > http://comments.gmane.org/gmane.network.openfabrics.enterprise/5371
> >
> > Is there anybody on here using SDP with DRBD that may have more information
> > on this?
> >
> > Seems a real shame as 40Gb SDP Infiniband sounds like a great solution!
> FWIW, based on our experience in direct point-to-point IB connections
> (no switching involved), DRBD-over-SDP often produced
> - little gains (if any) in throughput over IPoIB,
> - an actual increase in latency over IPoIB.

That may be so for a single connection.
Though the latency side of things can be tuned...

Once you go several DRBD, the aggregated throughput looks quite different.
You should also take the cpu usage into account.
IPoIB can become CPU limited. SDP does not consume much cycles, really.

: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

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