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 McWilliams 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?
14/9/10 17:50
Post a Comment

Popular posts from this blog

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 bluetooth The device doesn't allow step 2 if step 1 didn'...
12 comments
Read more

Reset lost root password on vSphere ESXi 6.7

VMware's solution to a lost or forgotten root password for ESXi is simple: go to  https://kb.vmware.com/s/article/1317898?lang=en_US  and you'll find that "Reinstalling the ESXi host is the only supported way to reset a password on ESXi". If your host is still connected to vCenter, you may be able to use Host Profiles to reset the root password, or alternatively you can join ESXi in Active Directory via vCenter, and log in with a user in the "ESX Admins" AD group. If your host is no longer connected to vCenter, those options are closed. Can you avoid reinstallation? Fortunately, you can. You will need to reset and reboot your ESXi though. If you're ready for an unsupported deep dive into the bowels of ESXi, follow these steps: Create a bootable Linux USB-drive (or something else you can boot your server with). I used a CentOS 7 installation USB-drive that I could use to boot into rescue mode. Reset your ESXi and boot from the Linux medium. Ident...
Post a Comment
Read more

GEM WS2 MIDI System Exclusive structure and checksums

MIDI is the standard for communication between electronic music instruments like keyboards and synthesizers. And computers! While tinkering with an old floppy-less GEM WS2 keyboard, I wanted to figure out the structure of their System Exclusive memory dumps. SysEx is the vendor-specific (and non-standard) part of MIDI. Vendors can use it for real-time instructions (changing a sound parameter in real-time) and for non-real-time instructions (sending or loading a configuration, sample set, etc.). In the GEM WS2, there's two ways of saving the memory (voices, globals, styles and songs): in .ALL files on floppy, and via MIDI SysEx. The .ALL files are binary files, 60415 bytes long. The only recognizable parts are the ASCII encoded voice and global names. The SysEx dumps are 73691 bytes long. As always in MIDI, only command start (and end) bytes have MSB 1, and all data bytes have MSB 0. The data is spread out over 576 SysEx packets, preceded by one SysEx packet with header informat...
23 comments
Read more