Skip to main content

Link aggregation between CentOS 5 and a SLM2024

It's been a while since I made time to try something new. This week, I finally took something off of the "need to try this" list: link aggregation. I've had a gigabit Ethernet switch with link aggregation for about a year now, and my main Linux box has 3 gigE NICs, but I was still only using one. Time for change.

Google found me some good documentation for channel bonding on CentOS5. Manually editing the ifcfg-eth{0,1,2}, ifcfg-bond0, and modprobe.conf is all that's required. That worked, but the default bonding setting is "balance-rr", the simplest loadbalancing algorithm. What I wanted to use was full IEEE 802.3ad link aggregation, mode 4 of the bonding module.

During testing, I got fooled into believing that "service network restart" unloaded and reloaded the bonding module. It doesn't, I should have tested using "service network stop; rmmod bonding; service network start" from the start. Learned my lesson, configured the switch into LACP mode (dynamic link aggregation instead of static), and I was on for some bandwidth testing.

I tried a couple of different bandwidth eaters, but floodping, NFS reads, didn't really stress the configuration. In comes netcat: "nc -l 5555 > /dev/null" on one side, and "nc myserver 5555 < /dev/zero" on the other, and you'll get a gigabit stream of data in no-time. Using dstat and a couple of netcats, the current record stands at more than 200 MBps. Mission accomplished !

Comments

Grant said…
So you never had any problems with the SLM2024 doing mode 4 channel bonding? I'm thinking of purchasing one for a College Cloud but there's a Newegg post that says channel bonding doesn't work on it.

The cloud will be between a bunch of XCP hosts (CentOS based).

Are you still running in this mode and do you see any reliability issues?

Popular posts from this blog

How to solve "user locked out due to failed logins" in vSphere vMA

In vSphere 6, if the vi-admin account get locked because of too many failed logins, and you don't have the root password of the appliance, you can reset the account(s) using these steps:

reboot the vMAfrom GRUB, "e"dit the entry"a"ppend init=/bin/bash"b"oot# pam_tally2 --user=vi-admin --reset# passwd vi-admin # Optional. Only if you want to change the password for vi-admin.# exitreset the vMAlog in with vi-admin These steps can be repeated for root or any other account that gets locked out.

If you do have root or vi-admin access, "sudo pam_tally2 --user=mylockeduser --reset" would do it, no reboot required.

Volkswagen UHV bluetooth touch adapter & its problems

My Volkswagen car has the "universal cellphone preparation" UHV built-in. This is the main part of a car kit, but requires an additional adapter for connecting to a cellphone. At first, I was using an adapter for my good old Nokia 6310, even after I changed to the Nokia E71. Connecting was easy: pair the phone with the "VW UHV" bluetooth entity, and done. This has the phone connected to the car kit at all times, so even non-call-related functions use the car audio system (e.g. voice recognition).
But progress will have its way, no matter what happens. So in comes the "bluetooth touch adapter". Instead of a phone-specific adapter, this is a small touchscreen device that slots into the UHV dashboard mount. Connecting a phone is very different now:
the Bluetooth Touch Adapter connects to the "VW UHV" device via bluetooth
the phone connects to "Touch Adapter" device, also via bluetoothThe device doesn't allow step 2 if step 1 didn't s…

Multiple VLANs on a Synology NAS

Synology, like other SOHO/SMB NAS vendors, touts VLAN functionality with their current DSM 4.1 software. However, the web interface just lets you specify one VLAN tag to use over each eth interface (or bond interface).
Manual approachIn the busybox environment that you can ssh into as root (after enabling ssh through the webinterface), there's all the tools you need to use multiple VLANs over one link (eth or bond), however:
First you insert the 802.1q module into the Linux kernel:
 /sbin/lsmod | /bin/grep -q 8021q || /sbin/insmod /lib/modules/8021q.koThen you add each VLAN you need to every interface (bond0 in this example)
 /sbin/vconfig add bond0 4And finally you can configure IP addresses on every interface.vlan combination (bond0.4 in this example)
 /sbin/ifconfig bond0.4 192.168.4.1 broadcast 192.168.4.255 netmask 255.255.255.0The same type of script would work on a QNAP NAS too, by the way. They offer 8021q.ko and vconfig in their commandline environment as well.
Packets from…