|
Trent 'Lathiat' Lloyd (トレント)
|
|
|
| Avahi is now 3 years old... |
[Aug. 25th, 2008|03:07 pm] |
| [ | Tags | | | avahi | ] |
| [ | Current Location |
| | sYra | ] |
| [ | Current Mood |
| |  accomplished | ] |
| [ | Current Music |
| | Linkin Park - No More Sorrow | ] |
I just noticed that as of a few days ago (22nd August) - Avahi is now 3 years old.
Heres my original release announcement:
http://lists.freedesktop.org/archives/avahi/2005-August/000227.html
That's a crazy amount of time, since then I presented at Linux.conf.au 2006 and GUADEC 2007 (Birmingham) as well as some presentations at GNOME mini-confs and the like.
Fun and games... also for anyone following this blog, I regularly twitter as lathiat
http://twitter.com/lathiat
Feel free to follow me, but it tends to be more personal stuff rather than Tech/Open-Source related |
|
|
| Avahi Scalability: "Is it good or is it bad?" |
[Feb. 28th, 2007|10:42 am] |
Lennart rightfully pointed out that I didn't really make any conclusion as to the results of my little test, the reason for this is really, "I'm not sure"
Certainly, It seems to be OK, the number of transmitted packets by my rough calculation, make sense, I would be interested to see what the realistic practical throughput of multicast on wireless is when you have many hosts transmitting at once, I know in 802.11b multicast is transmitted at "basic rate" of 1 or 2 mbit (or so I beleive), I'm not sure if 802.11g changes this.
My generally quick gut feeling is "I think this would work" (on wireless), I have no doubt this is fine on a wired network.
More testing to be done... |
|
|
| Some random non-scientific Avahi "scaling" figures |
[Feb. 27th, 2007|10:12 pm] |
| [ | Tags | | | avahi, olpc, xo | ] |
| [ | Current Location |
| | Home | ] |
| [ | Current Mood |
| | accomplished | ] |
Talking to sjoerd and others on IRC, (for the benefit of the OLPC project), I decided to attempt to get some kind of an idea of the amount of traffic Avahi generates on a large network.
I booted up 80 UMLs, running 2.6.20.2, on my AMD Athlon64 X2 4200+ (O/C to 2.5GHz per core), with 2GB of ram.
Each was running with 16M ram, a base debian etch install with Avahi 0.6.16.
Interestingly with 80 VMs running my memory usage looked like this:
Mem: 2076124k total, 2012064k used, 64060k free, 18436k buffers
Swap: 996020k total, 8k used, 996012k free, 1476504k cached
I configured a 'UML Switch' with a tap device on the host attached (tun1) and told each VM to come up and use avahi-autoipd to obtain a link-local IP.
I had each VM set to advertise 3 services, via the static service advertisement files
- _olpc_presence._tcp
- _activity._tcp (subtype _RSSActivity._sub._activity._tcp)
- _activity._tcp (subtype _WebActivity._sub._activity._tcp)
plus it was configured with Avahi defaults so it would announce a workstation service (the default 'ssh' service was however NOT present) and the magic services that indicate what kind of services are being announced
So I started Wireshark and IPTRAF and started booting 80 VMs, at a pace of 1 every 10 seconds, after roughly 10-15 minutes the following numbers of packets were seen on the host tun1 interface
704 UDP (56.3%)
390 ARP (21.2%)
156 OTHER (12.5%)
The ARPs are for avahi-autoipd and the UDP packets are for avahi-daemon to speak mDNS, iptraf reported
Incoming Bytes: 417,391
I then gave my local machine an IP which bumped the packet count to 712, 395 and 157.
I then started 'avahi-browse _activity._tcp', this would result in 2 services from each machine being returned, following that tidying up the packet count was at
935 UDP
Incoming Bytes: 496,901
Outgoing Bytes: 28,787 (30 packets according to iptraf)
Now this *really* gave me machine a heart attack, as many 'linux' processes we're eating 20% CPU as possible, and took a good 10+ seconds for my machine to start responding again, I suspect if i was running the SKAS3 patch it might be a little less harsh.
I then after cancelling that, run avahi-browse -r _activity._tcp which causes Avahi to resolve each of the services, following that run
UDP 1287
Incoming Bytes: 570,000 packets 1384
Outgoing Bytes: 185,000 packets 227
In this case most of the services were cached and I just had to resolve each one.
I forgot to watch for traffic counts, so I re-ran the above test and iptraf claimed 165kbits/second at peak for 1 5 second interval. In this time I noticed a bunch of the service resolution queries timed out, I suspect this may have to do with it causing my machine to lock hard for a bit while it does it's magic... ;)
So that's the end of my very simple basic run of basically doing some real (rather than theoretical) tests of the number of packets seen flying around with 80 hosts on a network with Avahi with a few services, and the impact of people running a browse/resolve on a popular service type.
I'm going to try comandeer some more hardware to run some faster tests and collect some more useful data. |
|
|
| Linux.conf.au 2007 |
[Oct. 17th, 2006|12:29 pm] |
| [ | Tags | | | avahi, linux.conf.au | ] |
| [ | Current Location |
| | Home | ] |
| [ | Current Mood |
| |  disappointed | ] |
| [ | Current Music |
| | Club 977 Hitz Streaming Ratio | ] |
Unfortunately, my paper for Linux.conf.au (on Avahi) was rejected, it's a bit of a shame given that (following last year) Avahi is now available in many distros, notably Fedora Core 5 seems to ship it and so will Ubuntu Edgy shortly - meaning more people are aware of it and may have been interested!
However I hope to still make it there, and will be there to talk to anyone who is interested about Avahi, or my long-standing tradition of talking about IPv6 support in your applications.
In addition, Lennart Poeterring, who is also behind much of the code in Avahi, will be attending, and I'm sure he'd be willing to talk to anyone as well! |
|
|
| Avahi becoming more ubiquitous |
[Oct. 12th, 2006|08:37 am] |
| [ | Tags | | | avahi | ] |
| [ | Current Location |
| | Work | ] |
| [ | Current Mood |
| |  working | ] |
I work at a co-location company (HostAway - http://www.hostaway.net.au/)
Just had a customer in installed Fedora Core 5 on their server today and much to my surprise when it rebooted...
"Starting Avahi daemon.... [OK]" |
|
|
| navigation |
| [ |
viewing |
| |
most recent entries |
] |
| [ |
go |
| |
earlier |
] |
| |
|
|
![[info]](http://l-stat.livejournal.com/img/userinfo.gif){kind=small}
lathiat's journal