Xenserver 7.1 slow performace with iscsi SAN

[nareshn2003]

Hi

I am learning iscsi SAN using StartWind SAN software installed on windows server 2012 R2 physical server. My setup is as shown in attached image. Basically i have two servers in pool installed with same version of XenServer 7.1 with patches. For SAN storage i created the windows server 2012 R2 on physical machine with two lan cards 1 Gbps and 10Gbps Dual link card.

My Setup is follow:

Xenserver1 :
- 4x 1Gbps LAN card
- Dual Port 10Gbps Lan Card

XenServer 2:
- 4x 1Gbps LAN card
- Dual Port 10 Gbps LAN card

StarWind SAN:
-1 x 1Gbps LAN Card
- Dual Port 10 Gbps LAN Card


1. XenServer1 and XenServer 2 is connected to StartWInd iSCSI SAN directly using Direct Attached Copper cable and also with 1 Gbps using switch.
2. Since I donot have 10 GBps switch so i did Bridge network where SAN installed for both 10Gbps link coming from XenServer 1 and 2 so both server can connect to same IP.
3. I setup multiIO as described in https://www.starwindsoftware.com/techni ... r-Pool.pdf
4. Both 192.168.1.215 and 10.0.0.1 IP are added to both xenservers in pool and show mpio active.
5. Able to create Storage device in XenCenter and Multipath shows 2 of 2 Path active on both server.


Problem is that speed is very slow even it take 8-10 minutes to start VM or sometime never starts. I seen the traffic on both lan card but in kbps.

Can anyone comment what is wrong with my setup ?

Diagram.jpg (64.99 KiB) Viewed 6252 times

[nareshn2003]

Hi
If i remove the bridge between two 10Gbps card then it works fine but it only allows to connect single xenserver in pool because as per my setup as given

xenserver1 iSCSI SAN
10.0.0.2 ------> 10.0.0.4

xenserver2 iSCSI SAN
10.0.0.3 --------> 10.0.0.5


So i can ping xenserver1 to iscsi SAN using 10.0.4 but 10.0.0.5 is not accessible due to Direct Attach Cable so my second server will not able to communicate
with 10.0.0.4.

So any idea how can i do without 10G switch ?


Naresh

[nareshn2003]

Change MTU to 1500 both side solved problem . Not sure why it doesnt worked on 9000

[Vitaliy (Staff)]

Hello Naresh,

Basically, enabling of Jumbo Frames could degrade the speed on 1 Gb channels.
In addition,when JF are enabled on 10 Gb channels and switch is only 1 Gb, them could freeze production.
It is known issue and in most cases depends on network adapter driver.