VMware

This Question is Answered

1 "helpful" answer available (6 pts)
9 Replies Last post: Nov 22, 2006 7:14 AM by wolfwolf  

Load balancing ISCSI? posted: Aug 9, 2006 5:56 PM

Click to view Osm3um's profile Hot Shot 228 posts since
May 18, 2005
I have got my ISCSI setup running against an AX150i, SPA has IPs 172.31.1.1 and 172.31.1.2, SPB has IPs 172.31.1.3 and 172.31.1.4. (NOTE: I read somewhere that having all four ports in the same network is not a valid config for a Linux box and it shoudl be 172.31.1.1, 172.31.2.1, 172.31.1.2 and 172.31.2.2!).

I have set both NICs to the same VSwitch and both nics are hard wired into a switch which is then connected to all four ports on the AX150i.

Viewing the performance of the ESX server via virtual center I can see there is no traffic going across the secondary NIC (unless I make it the primary NIC then it takes the traffic just fine). The failover works great as well so I know the connections are correct.

I have seen two locations to adjust load balancing one is in the Virtual switch and the other is the kernel.

So, how do I make the system balance the load across the two NICs? What option should I use for load balancing and in the switch and/or the kernel? Mac hash?

Thanks,
Bob

PS The load balancing on the ax150i with Powerpath when running Windows works great so I know (or think) it is not the AX150, but rather my configuartion in ESX.

Re: Load balancing ISCSI?

1. Aug 9, 2006 6:17 PM in response to: Osm3um
Click to view Paul Lalonde's profile Master 767 posts since
Jan 16, 2006
Hi Bob,

Unless someone wiser than myself can chime in, I don't believe iSCSI multipath for load balancing (aka MPIO, or multiple connections per session MCPS) is available in ESX 3.0.

From what I understand, only failover from a primary iSCSI connection is supported.

MPIO / MCPS rely on multiple TCP/IP connections ("logons") to the same iSCSI target within a singular session. Each TCP/IP connection can be different, ie. different src IP / dest IP addresses. At the iSCSI session layer, iSCSI packets are traditionally round-robined across each TCP/IP connection.

ESX 3.0 does not provide the ability to log in more than once to an iSCSI target, and even if it did, I don't think it provides the round-robin mechanism to aggregate throughput.

Sorry...

Paul

Re: Load balancing ISCSI?

2. Aug 9, 2006 6:27 PM in response to: Paul Lalonde
Click to view dwilliam62's profile Enthusiast 44 posts since
Apr 11, 2006
Paul is correct. There's no MPIO. (yet?) Even the Qlogic multipath support is failover only.

If you use multiple VMFS volumes with an iSCSI system that has more than one gigE interface and can load balance them, like the EQL array this can help you utilize more NICs at the same time. While not a perfect load balancing solution is does give you better performance. And you still have failover.

Regards,

Don

Re: Load balancing ISCSI?

5. Aug 23, 2006 2:13 PM in response to: Osm3um
Click to view nicko13170's profile Novice 11 posts since
Feb 1, 2006
Hello,

Thanks for the response, i see this strange behaviour too. (with software iscsi)

I put two netword card (team) on the VSwitch Iscsi, but there's only traffic on one port.

I'm done with ISCSI ... maybe Vmware could publish a whitepaper with all the restrictions.

yet i notice : no load balacing (multipath) for ISCSI, no support for Jumbo Frames. And problem with vlan tagging on the service console port.

I wish there's a upgrade for 3.0 with at least support for jumbo frames. I will look for performances issues with only one card

Re: Load balancing ISCSI?

6. Aug 24, 2006 2:32 PM in response to: nicko13170
Click to view a_user's profile Enthusiast 35 posts since
May 19, 2005
You just have to remember, iSCSI SAN's are not yet designed with the expectation of running actual apps's off them like their FC counterparts. They are meant as a cheap/er centralized storage array as opposed to a storage based application appliance.

Re: Load balancing ISCSI?

7. Aug 24, 2006 10:53 PM in response to: a_user
Click to view Paul Lalonde's profile Master 767 posts since
Jan 16, 2006
Hmm... I think the people at EqualLogic would vehemently dispute that statement! :-)

There are lots of whitepapers on various iSCSI implementations that show how well iSCSI stacks up to FC... particularly in multiple GigE NIC or 10GigE environments.

We're running an HP EVA 4000 with two shelves and 2Gbps FC, and the EqualLogic PS-100E unit easily matched its performance...

Paul

Re: Load balancing ISCSI?

8. Aug 25, 2006 2:19 AM in response to: a_user
Click to view pasikarkkainen's profile Enthusiast 100 posts since
Jan 17, 2006
a_user: That's not true.. There are lots of high performance and fault tolerant enterprise iSCSI SAN arrays available.

Take Equallogic for example.. each array has 60 000 IOPS and 300 MB/sec.. 10 that kind of boxes give you 600 000 IOPS and 3000 MB/sec, with automatic load balancing.. and they are much easier to manage than most FC arrays/SANs.

Message was edited by:
pasikarkkainen

Message was edited by:
pasikarkkainen

Re: Load balancing ISCSI?

9. Nov 22, 2006 7:14 AM in response to: dwilliam62
Click to view wolfwolf's profile Enthusiast 48 posts since
Aug 2, 2006
If you use multiple VMFS volumes with an iSCSI
system that has more than one gigE interface and can
load balance them, like the EQL array this can help
you utilize more NICs at the same time. While not a
perfect load balancing solution is does give you
better performance. And you still have failover.

We've an ESX Server running a few VMs with iSCSI volumes as raw disks, the iSCSI array is an EqualLogic device.

We've a few unused NICs on the ESX Server, how do we configure them to achieve load balancing between the different iSCSI volumes and fail over?

Thanks.

VMware Developer

SDKs, APIs, Videos, Learn and much more in the Developer community.

Learn More

Developer Sample Code

Increase your developer productivity with VMware API sample code.

Learn More

VMworld Sessions & Labs

Online access to the latest VMworld Sessions & Labs and online services.

Learn more

Purchase PSO Credits Online

Purchase credits to redeem training and consulting services online.

Buy Now

Community Hardware Software

View reported configurations or report your own.

Learn More

VMware vSphere

Come witness the next giant leap in virtualization.

Register Today

Communities