link aggregation: how?

Link aggregation is not working for me to a point of the server not being reachable: what could be the problem, and what are the best practices in this type of a (seemingly fairly common) setup?

Dell r730 with dual 10Gb NICs running Ubuntu 22.04 (Ubuntu 22.04.3 LTS (GNU/Linux 5.15.0-82-generic x86_64)) and serving up an iSCSI target to a VMware cluster.

The NICs are connected to 10Gb link-aggregated ports on two different (but interconnected - is "stacked" the right word") Meraki MS225 switches.

In Ubuntu, the NICs are "bonded":

  renderer: networkd
  ethernets:
    enp130s0f0:
      dhcp4: no
    enp130s0f1:
      dhcp4: no
  bonds:
    bond-00:
      interfaces: [enp130s0f0,enp130s0f1]
      addresses: [<IPv4>/24]
      dhcp4: no
      routes:
        - to: default
          via: <gateway_IP>
          metric: 100
      nameservers:
        addresses: [<ns01_IP>,<ns02_IP>]
        search: [localdom.local]
      parameters:
        mode: balance-xor
        mii-monitor-interval: 1

If the ports on the Meraki switches are not link-aggregated - all is good, except the speeds are a bit slower (~40%) compared to using just one 10Gb NIC. (I was hoping that "bonding" the NICs and then configuring link aggregation in Meraki would give us speeds a bit higher than those on a single NIC.)

If the ports on the Meraki switches however are link-aggregated - packet loss of >50%, and the server becomes (almost) unresponsive.

(No special configuration in VMware. ESXi 7.0u3, the 10Gb links are active-active, and otherwise it's all default. Can't configure iSCSI network port binding in VMware because the 10Gb NICs are used for general traffic, not just iSCSI.)

What am I doing wrong?

Configurations I've tried:

• Meraki: no special configuration, no link aggregation
  • Ubuntu: no link bonding, just two individually configured NICs each with its own IP: no issues, bandwidth ~10Gbps, only one link is used even with iSCSI multi-pathing.
  • Ubuntu: bonded links in "balance-rr", "balance-xor", "802.3ad", "balance-alb" modes: ~6Gbps (40% slower), both links are used, see no errors in Meraki.
• Meraki: link aggregation enabled
  • >50% packet loss, and generally unusable - regardless of bonding mode in Ubuntu (tried "balance-rr", "balance-xor", "802.3ad"). (Did not try w/o bonding - as it defeats the purpose.)

(I am thinking my next step is to disable LACP in Meraki and go back to individual NICs in Ubuntu with no bonding.)

Thanks!