igb Intel Gigabit Network Connection I350, lagg, vlan - increase mtu

[Michael Schuh]

> Hi,
>
> My server is running with 4 Gigabit NICs:
>
> igb0 at pci0:5:0:0:        class=0x020000 card=0x152115d9 chip=0x15218086
> rev=0x01 hdr=0x00
>      vendor     = 'Intel Corporation'
>      device     = 'I350 Gigabit Network Connection'
>      class      = network
>      subclass   = ethernet
> igb1 at pci0:5:0:1:        class=0x020000 card=0x152115d9 chip=0x15218086
> rev=0x01 hdr=0x00
>      vendor     = 'Intel Corporation'
>      device     = 'I350 Gigabit Network Connection'
>      class      = network
>      subclass   = ethernet
> igb2 at pci0:5:0:2:        class=0x020000 card=0x152115d9 chip=0x15218086
> rev=0x01 hdr=0x00
>      vendor     = 'Intel Corporation'
>      device     = 'I350 Gigabit Network Connection'
>      class      = network
>      subclass   = ethernet
> igb3 at pci0:5:0:3:        class=0x020000 card=0x152115d9 chip=0x15218086
> rev=0x01 hdr=0x00
>      vendor     = 'Intel Corporation'
>      device     = 'I350 Gigabit Network Connection'
>      class      = network
>      subclass   = ethernet
>
>
> those NICs are connected to switch with LACP aggregation:
>
> lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>
> options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
>          ether 00:25:90:c1:1d:18
>          inet6 fe80::225:90ff:fec1:1d18%lagg0 prefixlen 64 scopeid 0x8
>          nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
>          media: Ethernet autoselect
>          status: active
>          laggproto lacp lagghash l2,l3,l4
>          laggport: igb3 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
>          laggport: igb2 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
>          laggport: igb1 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
>          laggport: igb0 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
>
>
> Using this lagg interface I created 2 vlan interfaces:
>
> vlan14: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
> 1500
>          options=103<RXCSUM,TXCSUM,TSO4>
>          ether 00:25:90:c1:1d:18
>          inet 192.168.1.65 netmask 0xffffff00 broadcast 192.168.1.255
>          inet6 fe80::225:90ff:fec1:1d18%vlan14 prefixlen 64 scopeid 0x9
>          nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>          media: Ethernet autoselect
>          status: active
>          vlan: 14 parent interface: lagg0
>
>
> vlan900: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
> 1500
>          options=103<RXCSUM,TXCSUM,TSO4>
>          ether 00:25:90:c1:1d:18
>          inet6 fe80::225:90ff:fec1:1d18%vlan900 prefixlen 64 scopeid 0xa
>          inet 172.25.25.65 netmask 0xffff0000 broadcast 172.25.255.255
>          nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>          media: Ethernet autoselect
>          status: active
>          vlan: 900 parent interface: lagg0
>
>
> I would like to increase the MTU on cards, but I can't set it in any way:
>
> % sudo ifconfig igbX mtu 9000 [14:59:37]
> ifconfig: ioctl (set mtu): Invalid argument
>
>
> event setting the MTU to 1500 (default value) results in same error.
> same for lagg0, and vlanX
>
>
> How can I increase the MTU for lagg interface ?
> Is it possible without rebooting or only via /etc/rc.conf ?
>
> Regards,
> --
> Marek Salwerowicz
>

Hi Marek,

if i remember well the order of doing so is important.

#1 set the mtu on each physical NIC to 9000
#2 create the lagg
.
.
.
on a running system it might consist of: destroy the vlans, destroy the
lagg,
set the mtu on each nic and rebuild the lagg and add the vlans.


HTH

regards

michael