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alexcrow
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Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Thu Mar 16, 2023 6:21 pm

Hi
I'm running a few CRS504s in production to give 25Gb connections to 2 oVirt/RHV servers. For the VM to public interfaces, one server is on a bond on a single switch, and the other is on a bond across two switches with MLAG, one of which is running 7.6, and the other running 7.7 (then 7.8).

The big problem is that when we migrate VMs from one host to the other, or even shut them down, if they were on the switches with the MLAG, most of the time the MAC address of the VM will never be removed from the Bridge Hosts table on the one switch running >= 7.7, and this causes ARP issues and broken communication to the VM. On the same MLAG pair, the other switch running 7.6 is fine, the MAC address goes away within the bridge aging time. The only way I can clear the MAC address is to down and up the bond interface.

Has anyone come across this on this switch or other modules with RoS >=7.7? As I understand the E flag on the MAC address means it's stored in the switch chip CAM. But I don't understand why it's not cleared when the host drops off the port.

I will do a downgrade later and see if makes a difference.

Any help much appreciated.
 
alexcrow
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Re: Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Mon Mar 20, 2023 11:22 pm

I've reverted all 504's to 7.6, and the same issue persists, but only on the same switch that had the problem before. Doesn't even need a migration to do it, I've managed to trigger it just by shutting down the VM, and the MAC address will stay in the table for days. If I change the TX mode on the bond it will immediately clear the MAC.

If anyone else has seen this issue, please respond. Been through the config on all 504's many times and nothing is different between them other than their IP addresses and VLAN-port assignment.
 
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Re: Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Wed Mar 22, 2023 3:11 am

MLAG issues have been seen sporadically at the forum, maybe not ready for production yet
 
blimbach
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Re: Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Thu Mar 23, 2023 2:23 pm

Hello all,

I unfortunately have similar experience and have opened tickets with support: SUP-111471 and SUP-107382.

Unfortunately, the experience with M-LAG on Mikrotik has been disastrous so far, although we use MC-Lags with other manufacturers (IBM/Lenovo/FS) without any problems.

The exchange of local MAC addresses (VLAN/CPU port on bridge) and MAC addresses behind the switch pair does not seem to work.

This is really not nice with multiple ESX servers and moving VMs.

I hope support/development can resolve this in the short term.
-Boris
 
alexcrow
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Re: Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Thu Mar 23, 2023 6:49 pm

Hello all,

I unfortunately have similar experience and have opened tickets with support: SUP-111471 and SUP-107382.

Unfortunately, the experience with M-LAG on Mikrotik has been disastrous so far, although we use MC-Lags with other manufacturers (IBM/Lenovo/FS) without any problems.

The exchange of local MAC addresses (VLAN/CPU port on bridge) and MAC addresses behind the switch pair does not seem to work.

This is really not nice with multiple ESX servers and moving VMs.

I hope support/development can resolve this in the short term.
-Boris
Hah, that's not great at all. I purchased these devices on the specs that said they would do MLAG. Bugger.
Mikrotik guys - ant chance of getting this fixed? I will have to to a live re-architecting if it's not, which means weekend work, which means a tired and grumpy me.

Thanks both for the insight.
 
alexcrow
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Re: Nasty issue with MAC address stuck on CRS504 with RoS >= 7.7

Thu Mar 23, 2023 6:55 pm

Hello all,

I unfortunately have similar experience and have opened tickets with support: SUP-111471 and SUP-107382.

Unfortunately, the experience with M-LAG on Mikrotik has been disastrous so far, although we use MC-Lags with other manufacturers (IBM/Lenovo/FS) without any problems.

The exchange of local MAC addresses (VLAN/CPU port on bridge) and MAC addresses behind the switch pair does not seem to work.

This is really not nice with multiple ESX servers and moving VMs.

I hope support/development can resolve this in the short term.
-Boris
Oh, BTW, is this only on the 504's or does it affect other devices? Because we're having a lot of ICMP loss to edge devices connected to MLAG'd CRS317s, such that monitoring them is not exactly productive (alerts every 2 minutes for each device).

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