MPIO Issues

I am using iSCSI between Windows 2003 Server and an HDS iSCSI four port Array.
The setup provides near theoretical maximum throughput with One 1GB NIC card.

We wanted to increase the iSCSI bandwidth to 2 GB so we added another 1GB
NIC to the server and configured iSCSI to support MPIO with an assumption
that if we use an Active-Active mode we could create a 2 GB network channel
for iSCSI.

MPIO configuration recognizes all LUNS as Multi-Path enabled. However, since
HDS is not approved by Microsoft I had to manually force the server to accept
each discovered LUN.

When we ran the load I found that MPIO picked up only one NIC card (one with
lowest IP address) for communication but never used the other NIC essentially
only providing us with 1GB iSCSI channel only. We have tried Round Robin and
Least Queue Depth modes and found similar results. However, in failover mode
MPIO works as expected and uses the 2nd NIC when 1st NIC is unplugged.

My question is can we use MPIO for creating parallel iSCSI channels? If yes,
what are the limitations as I may be adding more NICs?

Thanks

Rajesh

Sounds like you may have both sessions using the same NIC. When logging into
the target, make sure you explicitly specify the initiator source IP address.

"Rajesh" wrote:
[color=blue]
> I am using iSCSI between Windows 2003 Server and an HDS iSCSI four port Array.
> The setup provides near theoretical maximum throughput with One 1GB NIC card.
>
> We wanted to increase the iSCSI bandwidth to 2 GB so we added another 1GB
> NIC to the server and configured iSCSI to support MPIO with an assumption
> that if we use an Active-Active mode we could create a 2 GB network channel
> for iSCSI.
>
> MPIO configuration recognizes all LUNS as Multi-Path enabled. However, since
> HDS is not approved by Microsoft I had to manually force the server to accept
> each discovered LUN.
>
> When we ran the load I found that MPIO picked up only one NIC card (one with
> lowest IP address) for communication but never used the other NIC essentially
> only providing us with 1GB iSCSI channel only. We have tried Round Robin and
> Least Queue Depth modes and found similar results. However, in failover mode
> MPIO works as expected and uses the 2nd NIC when 1st NIC is unplugged.
>
> My question is can we use MPIO for creating parallel iSCSI channels? If yes,
> what are the limitations as I may be adding more NICs?
>
> Thanks
>
> Rajesh
>
>
>[/color]

We did consider this. The Source IP addresses are verified to be different
for different NICs. iSCSI Initiator is configured to use both IP Addresses.

Rajesh

"Thieu [MS]" wrote:
[color=blue]
> Sounds like you may have both sessions using the same NIC. When logging into
> the target, make sure you explicitly specify the initiator source IP address.
>
> "Rajesh" wrote:
>[color=green]
> > I am using iSCSI between Windows 2003 Server and an HDS iSCSI four port Array.
> > The setup provides near theoretical maximum throughput with One 1GB NIC card.
> >
> > We wanted to increase the iSCSI bandwidth to 2 GB so we added another 1GB
> > NIC to the server and configured iSCSI to support MPIO with an assumption
> > that if we use an Active-Active mode we could create a 2 GB network channel
> > for iSCSI.
> >
> > MPIO configuration recognizes all LUNS as Multi-Path enabled. However, since
> > HDS is not approved by Microsoft I had to manually force the server to accept
> > each discovered LUN.
> >
> > When we ran the load I found that MPIO picked up only one NIC card (one with
> > lowest IP address) for communication but never used the other NIC essentially
> > only providing us with 1GB iSCSI channel only. We have tried Round Robin and
> > Least Queue Depth modes and found similar results. However, in failover mode
> > MPIO works as expected and uses the 2nd NIC when 1st NIC is unplugged.
> >
> > My question is can we use MPIO for creating parallel iSCSI channels? If yes,
> > what are the limitations as I may be adding more NICs?
> >
> > Thanks
> >
> > Rajesh
> >
> >
> >[/color][/color]

Please send the output of "iscsicli sessionlist"

"Rajesh" <Rajesh@discussions.microsoft.com> wrote in message
news:11D4C61D-7644-41B3-883F-92471E9FF6DB@microsoft.com...[color=blue]
> We did consider this. The Source IP addresses are verified to be different
> for different NICs. iSCSI Initiator is configured to use both IP
> Addresses.
>
> Rajesh
>
> "Thieu [MS]" wrote:
>[color=green]
>> Sounds like you may have both sessions using the same NIC. When logging
>> into
>> the target, make sure you explicitly specify the initiator source IP
>> address.
>>
>> "Rajesh" wrote:
>>[color=darkred]
>> > I am using iSCSI between Windows 2003 Server and an HDS iSCSI four port
>> > Array.
>> > The setup provides near theoretical maximum throughput with One 1GB NIC
>> > card.
>> >
>> > We wanted to increase the iSCSI bandwidth to 2 GB so we added another
>> > 1GB
>> > NIC to the server and configured iSCSI to support MPIO with an
>> > assumption
>> > that if we use an Active-Active mode we could create a 2 GB network
>> > channel
>> > for iSCSI.
>> >
>> > MPIO configuration recognizes all LUNS as Multi-Path enabled. However,
>> > since
>> > HDS is not approved by Microsoft I had to manually force the server to
>> > accept
>> > each discovered LUN.
>> >
>> > When we ran the load I found that MPIO picked up only one NIC card (one
>> > with
>> > lowest IP address) for communication but never used the other NIC
>> > essentially
>> > only providing us with 1GB iSCSI channel only. We have tried Round
>> > Robin and
>> > Least Queue Depth modes and found similar results. However, in failover
>> > mode
>> > MPIO works as expected and uses the 2nd NIC when 1st NIC is unplugged.
>> >
>> > My question is can we use MPIO for creating parallel iSCSI channels? If
>> > yes,
>> > what are the limitations as I may be adding more NICs?
>> >
>> > Thanks
>> >
>> > Rajesh
>> >
>> >
>> >[/color][/color][/color]