Jumbo frames (mtu 9000) on Debian 7.10 servers with BCM57800 NIC (bnx2x)

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Jumbo frames (mtu 9000) on Debian 7.10 servers with BCM57800 NIC (bnx2x) – Managing your servers can streamline the performance of your team by allowing them to complete complex tasks faster. Plus, it can enable them to detect problems early on before they get out of hand and compromise your business. As a result, the risk of experiencing operational setbacks is drastically lower.

But the only way to make the most of your server management is to perform it correctly. And to help you do so, this article will share nine tips on improving your server management and fix some problem about linux, debian, mtu, broadcom, jumboframes.

I’m working on 2 servers under Debian 7.10 with Broadcom Corporation NetXtreme BCM57800 1/10 Gigabit ethernet.

I have done the following for both servers:

ethtool -g eth0
Ring parameters for eth0:
Pre-set maximums:
RX: 4078
RX Mini: 0
RX Jumbo: 0
TX: 4078
Current hardware settings:
RX: 4078
RX Mini: 0
RX Jumbo: 0
TX: 4078

I changed mtu to 9000 with:
ifconfig eth0 mtu 9000

ifconfig eth0
value has changed:

UP BROADCAST RUNNING MULTICAST MTU:9000 Metric:1

But it doesn’t work when I try to send 9000 bytes packet with:
ping -M do -s 8972 10.0.0.3
PING 10.0.0.3 (10.0.0.3) 8972(9000) bytes of data.
^C
--- 10.0.0.3 ping statistics ---
13 packets transmitted, 0 received, 100% packet loss, time 12095ms

However it is still working with 1500 bytes packets:

ping -M do -s 1472 10.0.0.3
PING 10.0.0.3 (10.0.0.3) 1472(1500) bytes of data.
1480 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=0.054 ms
1480 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.041 ms

NIC firmware:

/sbin/modinfo bnx2x
filename: /lib/modules/3.16.0-4-amd64/kernel/drivers/net/ethernet/broadcom/bnx2x/bnx2x.ko
firmware: bnx2x/bnx2x-e2-7.8.19.0.fw
firmware: bnx2x/bnx2x-e1h-7.8.19.0.fw
firmware: bnx2x/bnx2x-e1-7.8.19.0.fw
version: 1.78.19-0
license: GPL
description: Broadcom NetXtreme II BCM57710/57711/57711E/57712/57712_MF/57800/57800_MF/57810/57810_MF/57840/57840_MF Drive

Am I missing something here ?

Solution :

Most likely the switch isn’t letting the packets through. Some pcaps might also be diagnostically useful.

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