[dm-devel] understanding of multipathing and speed

[Bart Coninckx]

On Monday 05 July 2010 20:58:30 Christophe Varoqui wrote:
> On lun., 2010-07-05 at 20:37 +0200, Bart Coninckx wrote:
> > Hi,
> >
> > I would like to run my ideas by this list about multipathing and the
> > results as far as storage speed is concerned.
> >
> > I'm using multipathing to two iSCSI targets pointing to the same storage.
> > It was my understanding that this provides for network path redundancy
> > (and it does, I tested this) but also for added speed.
> > I did some tests with Bonnie++ however while both paths were active and
> > one path was down and the results are basically the same.
> >
> > Am I assuming wrong things? Or have I configured things wrong?
> 
> can you also include a 'multipath -l' output and sketch the
> hba/switch/controller physical connections ?
> 
> thanks,
> 

Sure,

xen3:~ # multipath -l
lx03 (1494554000000000000000000010000000000000002000000) dm-3 IET,VIRTUAL-DISK
[size=10G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=-2][active]
 \_ 2:0:0:0 sdc 8:32  [active][undef]
 \_ 1:0:0:0 sdb 8:16  [active][undef]
ws033 (1494554000000000000000000010000000100000002000000) dm-2 IET,VIRTUAL-
DISK
[size=15G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=-2][active]
 \_ 2:0:0:1 sde 8:64  [active][undef]
 \_ 1:0:0:1 sdd 8:48  [active][undef]
ms01 (1494554000000000000000000010000000200000002000000) dm-1 IET,VIRTUAL-DISK
[size=40G][features=1 queue_if_no_path][hwhandler=0]
\_ round-robin 0 [prio=-2][active]
 \_ 1:0:0:2 sdf 8:80  [active][undef]
 \_ 2:0:0:2 sdg 8:96  [active][undef]

I have two Gigabit NICs in this server each running over a separate switch to 
a separate gigabit NIC with a unique IP address on the storage IET iSCSI 
target.

Is this sufficient info?

Thx,

Bart