What is suggested configuration for use multipath with netapp hp procurves and rhevh?

Comments

My production rhev3.2 environment is runnig on infrastructure like this:
- 2x netapp fas2020a dual controlled but for simplicity i'm skipping partner controllers and its network. There are named budlight and pilsen
- 3x fujtisu rx200 as RHEV-H named as a1,a2,a3
- 1x fujitsu rx100 as RHEV-M named as rhevm
- 2x hp procurve 2910-24 switches as SAN switches named as procurve1 and procurve2
- 2x dlink switches for WAN, display, management and migration

HP switches are interconnected on backplane. And there is default port based vlan(vid 5). Note that HP switches cannot create LACP trunk across switches.
Netapp fillers has 2 nics(e0a,e0b) while e0a is connected to procurve1 and e0b to procurve2 both as the same. Netapp nics are configured as static multiMode.
Hypervizors have 4 nic (2onboard and 2 on additional dualport nic). While onboards are dedicated one for wan and second for display, management and migration. Additional nics is dual port while port1 is connected to procurve1 and port2 to procurve2 and bonded as balance-tlb.
Jumbo frames are enabled on all

iscsi ip adress are assigned as follows:
- budlight: 10.0.0.6
- pilsen: 10.0.0.30
- a1 (RHEV-H): 10.0.0.110
- a2 (RHEV-H): 10.0.0.120
- a3 (RHEV-H): 10.0.0.130

There are some iscsi targets on budlight. Pilsen is not exporting anything, but is hosting snapmirrored(replicated) volumes from budlight for DR.

There are some performance limitations of this setup and i think it can perform faster. Current write performance in virtuals is about 35
MB/s using dd

Q1:
Some tips online are pointing that iscsi is performing better with multipath configuration. They are suggesting add more nic aliases on target side and let initiator distribute load accross paths. Is that true? Is that true with RHEV-H hypervizors?

Q2:
I'm not sure if is better to configure netapps nics as "bonding" with ip aliases or as singles with aliases. What are your suggestions?

Q3:
What is recommended way to update iscsi storage domain to use multipath?

Q4:
I know that to use iscsi multipath with rhev and it must use separate subnet per path. How can i add separate subnet to nic bonding with vlan tagging disabled?

Q5:
How can i update rhev to vlan tagged networking without stopping cluster? I know how to do that on netapp and switch side. But i'm not sure what are right steps to that in rhev with RHEV-Hs.

Q6:
How to configure netapp switches. Enable spanning tree? Enable iscsi vlan thru interconnect?