HA with load balance all retransmission

[Lucas_Piris]

Hi,

We have a Fortigate HA with load balance all enabled, and we are monitoring the behavior, and I can see many retransmissions between slave and master, just when the slave unit process the packet, see this picture:

Anyone known if this is normal? when we have load balance all enabled?

Regars

Lucas

[vjoshi_FTNT]

Hello Lucas,

Yes, it is possible if the traffic is high. load-balance-all option will make the primary unit load balance all TCP sessions.

It really doesn't help to improve the throughput because of extra overhead required for load balancing. So load-balance-all is disabled by default.

[Lucas_Piris]

Hi vjoshi,

Thanks.

The strange thing is that this environment is lab, has no charge. :(

Regards

Lucas

vjoshi wrote:

Hello Lucas,

Yes, it is possible if the traffic is high. load-balance-all option will make the primary unit load balance all TCP sessions.

It really doesn't help to improve the throughput because of extra overhead required for load balancing. So load-balance-all is disabled by default.

[vjoshi_FTNT]

Hello Lucas,

Sorry, what do you mean by 'no charge'?

If it is in lab and you are testing this, fine.

If this is just a test bed and you are planning for a production setup, and if you really want to use the HA for optimum load balancing, I would suggest virtual clustering with VDOMs.

This is possible in a-p mode where each device will be master for specific VDOMs and other device will serve as Slave unit.

Cheers,

lpiris wrote:

Hi vjoshi,

Thanks.

The strange thing is that this environment is lab, has no charge. :(

Regards

Lucas

[Lucas_Piris]

Hi Joshi,

Sorry, I wanted to talk without load.

Actually we have a HA in production, And we have this behavior.

So, We made lab with two 110C FG and we can see the same behavior.

Regards

Lucas

vjoshi wrote:

Hello Lucas,

Sorry, what do you mean by 'no charge'?

If it is in lab and you are testing this, fine.

If this is just a test bed and you are planning for a production setup, and if you really want to use the HA for optimum load balancing, I would suggest virtual clustering with VDOMs.

This is possible in a-p mode where each device will be master for specific VDOMs and other device will serve as Slave unit.

Cheers,

lpiris wrote:

Hi vjoshi,

Thanks.

The strange thing is that this environment is lab, has no charge. :(

Regards

Lucas

[vjoshi_FTNT]

Hello Lucas,

I got it. It is strange it happens without load.

Is it causing any specific issue to the application?

[Lucas_Piris]

Hi Josh,

Yes! this customer have an internal application that are impacted.

We had to change ha mode to a-p, and it works fine.

I will monitoring anothers HA, To see if I can find the same behavior.

Cheers

Lucas

vjoshi wrote:

Hello Lucas,

I got it. It is strange it happens without load.

Is it causing any specific issue to the application?

[vjoshi_FTNT]

Hello Lucas,

Do you see the same behavior in your lab setup as well?

[Lucas_Piris]

Hi Josh,

yes.

vjoshi wrote:

Hello Lucas,

Do you see the same behavior in your lab setup as well?

[vjoshi_FTNT]

Hello Lucas,

Weird, I expect it to happen, but without any traffic doesn't seem to be correct.

I would recommend not to use the load balance all, instead use the virtual cluster for effective load sharing.