Re: [Server-devel] notes on scaling ejabberd for the XO's
More info available on the wiki at: http://wiki.laptop.org/go/Ejabberd_Configuration#Patches On 3/11/09, Bryan Berry br...@olenepal.org wrote: Here are some notes from a short IRC conversation I had w/ Rob Mcqueen, the lead developer of Telepathy transcript of conversation on #sugar bemasc: bernie: I am concerned about the fact that in the default schoolserver set up all users are in one giant shared roster Robot101 RESOLVED, ALREADYFIXED (but not in any deployments, or in the UI) BryanWB and the resulting chatter slows down the XO/Sugar considerably? Robot101 yes Robot101 rwh the latest versions of sugar and telepathy support using an XMPP component called gadget instead of the shared roster BryanWB Robot101: so gadget fixes this? Robot101 yup Robot101 rwh you only receive push notifications about a) what Sugar has searched for/displaying on the neighborhood view, or b) your friends -- hgcphoenix (n=hc...@124.107.253.193) has joined #sugar BryanWB Robot101: neat, and does it work together w/ the XS? Robot101: which version of sugar is it in? -- hgcphoenix (n=hc...@124.107.253.193) has left #sugar Robot101 they went off on a complete tangent trying to hack shared rosters to have less mutually visible sets of people we thought of that but also decided it was the bong, so we fixed it properly with gadget. BryanWB Robot101: what is the testing status of gadget? Robot101 it's deployed on jabber.sugarlabs.org (which is on collabora.co.uk) seems to work fine, ejabberd seems to gradually leak memory though, which isn't too great maybe a little much CPU usage on gadget, but nothing you couldn't profile and I'm not familiar enough with the sugar release cycle to say where the support went in Robot101 rwh eu daytime is better to find the Sugar devs and the Collaborans who worked on Gadget (cassidy, daf) BryanWB Robot101: ok, will talk w/ them later today Robot101 gadget was always our plan, it just took us a while to get to it BryanWB Robot101: by the way last year we tested ejabberd by streaming your video talk on Telepathy to 80 XO's bemasc Robot101: I believe martin dropped the shared roster, and inside is simply using moodle to set all rosters directly. s/inside/instead/ bemasc bernie benzea Robot101 bemasc: so it's still shared as in server-enforced mutual visibility, just in smaller groups. bemasc right, but from ejabberd's perspective, it's individual rosters Robot101 that's exactly how shared rosters always work Robot101 the client thread gets a copy of the same roster at sign in bemasc oh? I thought there was a patch to ejabberd required. Robot101 yes, he's patched it to source the shared roster from moodle, I'd imagine bemasc martin seemed to say that he could use a totally stock ejabberd Robot101 oh, right. sql query or something. our patches were just extending the built-in shared roster to a) work properly (deal with dynamic additions and removals) and b) support a group of online users rather than everyone -- Bryan W. Berry Technology Director OLE Nepal, http://www.olenepal.org ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
Rangan, I remember the Linksys routers used to drop connection, as soon as 33-34 clients were logged in, and as Bryan mentioned we got much better perfomance with the readily available Taiwanese brand of APs. With a Linksys 25 odd clients works just fine though with heavy traffic. With the Linksys WRT54G /L/S variants, its important to note the version (eg 5.1/ v6/ v8) and chip used (Atheros/ Broadcom) as only certain versions support full funtionality, with opensourced firware. Here's a good table to refer to: http://www.dd-wrt.com/wiki/index.php/Supported_Devices Cheers, Dev On 3/10/09, Rangan Srikhanta ran...@laptop.org.au wrote: Folks, Here at OLPC AU, we are using Linksys WRT54GLs using DD-WRT and configuring the routers to act as an AP according to the following instructions. http://www.dd-wrt.com/wiki/index.php/Wireless_Access_Point I found I could turn the WRT54GL into the required AP mode in 10minutes, using an XO. In our first round of deployments we will be only using WRT54GLs, and after speaking to Dev, will be working on 1 for every 25. Thx, Rangan *From:* server-devel-boun...@lists.laptop.org [mailto: server-devel-boun...@lists.laptop.org] *On Behalf Of *Reuben K. Caron *Sent:* Tuesday, 10 March 2009 11:29 PM *To:* Daniel Drake *Cc:* server-devel *Subject:* Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare? Daniel Drake wrote: 2009/3/9 Bryan Berry br...@olenepal.org br...@olenepal.org: We will have roughly 8+ AP's. We have found that off-the-shelf AP's can handle around 60-70 users. But that doesn't still doesn't solve the problem of the XO's getting bogged down by tons of ejabberd chatter. DSD: do you have any ideas about this? Have only had a chance to test numbers on Linksys WRT54Gsomething routers, which stop accepting new connections after 33 users. yay. Have you tried loading a different firmware on these, dd-wrt? ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
Re: [Server-devel] Wireless Cards in the School Server
On 3/9/09, Marten Vijn i...@martenvijn.nl wrote: On Mon, 2009-03-09 at 17:51 +, Dev Mohanty wrote: You could also use the APs in repeater mode with the same SSID, if you're planning to use more then one AP. no that is no very handy if want some performance, a repeater eats bandwidth from the AP. True, using an AP as a reapeater does compromise on your bandwidth, guess its only helpful in cases where you're wanting to extend coverage and not ness improve connectivity. Best for performance - big antenna's antenna's (reduces noise from clients) - channel planning - ap's in bridging mode (no routing or NAT) *Configuring your APs to use different channel from one another. In a classic E.U (U.S.?) - a server is in a server room - ap is in the class room - maybe use PoE (803.af) over your wired network best, Marten ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
Bryan I assume, this is in reference with the deployment planned at the new schools, and guess am more then familiar with admin workload and power limitations you happen to mention in Nepal. Hence was wondering if you've looked into the option of using more then one XS, installed at the same location (eg DOE, OLE) if not at the schools, this might make it a lot easier to administer. One XS could cater to students in 3 schools while the other could register students/XOs from the other two schools, for load balancing.. As am not too sure that using additional RAM would get the desired results. And ofcourse there's the 4GB RAM limitations on a 32bit processor, unless you plan to use a PAE switch and tweak the kernel too and guess that would be getting into murky waters. Besides, as Martin pointed out using a 64bit processor would require the XS iso to be completely rebuilt, which might take a while forthcoming. Though, I've heard that AMD's Athlon processors are backward compatible with 32bit applications and permit use of more then 4GB RAM without PAE, guess food for thought if you're adamant on using just one XS for all the schools to reduce the overhead. But still believe getting ejabberd to perform with 400 simultaneous users, might still be a tough task. Cheers, Dev On 3/8/09, Bryan Berry br...@olenepal.org wrote: On Sun, 2009-03-08 at 13:33 +1300, Martin Langhoff wrote: Bryan, I'm on the road, apologies if I'm a bit succint... - 400 users are unlikely to be online at the same time, supporting all users online at the same time will stress all the infra, so the path to success is, I suspect, paved with strategies to define usage patterns that avoid clustering everyone at the same time. But 200-300 users could be online at once. I think it will be too complicated to tell some of them: Don't connect to the AP right now, you may overwhelm ejabberd - I am working on 0.6 which will let you partition the school -- instead of @online@, large schools can set moodle+ejabberd in a mode where users are in a shared-roster-group defined by their course membership in moodle. I've posted on the list and written in the wiki about this before if you need more detail. - More users - more RAM to the server :-) and disk space for backups we can provide that - Do you really have a low latency / high bw conn between the schools and the location with the XS? I have the feeling we had this conversation before... :-) and I suggested smaller and local, which is how the XS is designed to work. That's still my recommendation... The XS is quite a complicated ensemble of software having an XS at every school magnifies the administration work. Having a centralized XS for several schools can dramatically reduce administrative overhead. Additionally our schools only have about 8 hours of electricity per day. I am concerned about the XS losing power suddenly multiple times per day. We have a relatively low latency connection b/w the schools and the XS. We have discussed these issues before and I believe that we both came to the conclusion that Nepal has different requirements than some of the other pilot schools. -- Bryan W. Berry Technology Director OLE Nepal, http://www.olenepal.org ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
Re: [Server-devel] Wireless Cards in the School Server
Hi Xavier, You could also look up the archive at http://lists.laptop.org/pipermail/networking/ Guess hasn't been very active lately, but then has plenty of info and reference to the wiki. Should get you started and help you with most of your queries. Cheers, Dev On 3/8/09, Xavier Ziemba xavier.zie...@students.olin.edu wrote: I've been working on configuring an XS server for the Cambridge Friends School in Massachusetts and have a couple of questions regarding wireless networking and the XS server. Does the XS software support automatic configuration of PCI wireless cards within the server itself? The documentation on the OLPC wiki seems to suggest that using separate wireless access points through a wired interface is supported; would this be a better solution for this deployment? Also, how would I go about configuring the appropriate links between network interfaces if I used wireless cards within the server? Thanks, Xavier Ziemba ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
Re: [Server-devel] Ubuntu XS
Would be interesting to know more on Uruguay's Debian based XS.. any links? Besides, if I remember correctly, I guess Tony Pearson was also part of that team or maybe not. I have mixed feelings about the current XS builds, guess I'd have preferred the XS being a lot more efficient and to run out of the box then what one gets off the latest image, as I believe a considerable amount of time has gone into it. On the other hand am not too sure if changing to core OS would resolve anything, it's more about getting the right packages in and getting them to function as required. Maybe at this point it makes sense resolving the bugs with the current XS, instead of trying to port it to a Debian based distro. As Martin points out the non-functional 80% kind of stands out. But then if you guys do eventually decide to have two concurrent versions of the XS and plan for a Debian based XS.. count me in on it. Maybe competition for good is the need of the hour! Cheers, -Dev- Michael Stone wrote: On Mon, Aug 18, 2008 at 07:41:13AM +1000, Pia Waugh wrote: There are a few interesting feature requests I've had from local trials, including the ability to only allow an XS to talk to approved XOs, to avoid strangers parking outside a school with an XO and interacting with children (worst case scenarios are always the first thing on a Government agenda :), so we're looking at MAC address management on the server potentially. More to come! Uruguay already uses a Debian-basex XS (which is quite different from Martin's) and which includes some MAC-address filtering technology. (They've also expressed great interest in expanding this technology into a full 802.11i/802.1x/EAP/RADIUS authentication system, which seems like it might be of mutual interest.) Greg Smith and Emiliano Pastorino could probably give you some good introductions if you'd like to try to collaborate with LATU. Michael ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
