asp24
Enthusiast
Enthusiast

Load balance iscsi, use only specific paths

Is it possible to load balance (RR) between only certain iscsi paths? I have two Starwind iscsi SAN's setup in Active-Active HA mode, but one node is SSD based and the other is SAS-based.

Performance is much better when using fixed path to the SSD node. As I have multiple paths to each node it would be great to be able to load balance between these paths (but ONLY the paths to the SSD iscsi node).

Is it possible to RR load balance between specific paths only?

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6 Replies
asp24
Enthusiast
Enthusiast

Is it really not possible to use Round Robin load balancing on lets say half of the paths? Only one or ALL?

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Rumple
Virtuoso
Virtuoso

So in other words, you want to run a active/passive configuration to your target, not an active/active (since you don't want anything loading the data from the SSD Node unless its not available)

Took a look at the node configuration info and I'd have to guess that the best approach would be to use FIXED and make the path that goes to the SSD Host IP the active path....this will force traffic to the correct Virtual HA Node...and the other one will not see any traffic

If the SSD goes offline, the paths will switch to the other HA node until the primary comes back online

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asp24
Enthusiast
Enthusiast

I want the host to use multiple paths to the SSD SAN (not just one), and only failover to the SAS-paths if all paths to the SSD SAN is down.

I have 4 paths to the SSD-SAN and 4 to the SAS-SAN.

The performance is very good using ONE fixed path to the SSD-SAN, but I'm limited to a single gigabit link.

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AndreTheGiant
Immortal
Immortal

Thread has been moved in the vStorage area.

Which kind of SAS storage are you using?

Have you considered to build more LUN to use different path for each?

Andre | http://about.me/amauro | http://vinfrastructure.it/ | @Andrea_Mauro
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asp24
Enthusiast
Enthusiast

The SAS storage is 32x 15k 300GB disks on a Starwind node (and the other node is SSD)

I CAN load balance that way, but I will not get more than 1Gbit to a single VM that way.

I have ONE host using 10Gbit nic, and that VM get 800-900 MB/s transfers. But I can not afford 10Gbit for all hosts right now. I only have 3750E switches (with 2 10G-slots)

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asp24
Enthusiast
Enthusiast

The recent (beta) of Starwind supports ALUA. So when this is released as non-beta this will solve my problem.

I have tested already, and when I enable round robin, only paths to the primary node is used for LUN's where AULA is enabled.

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