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 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 > RESOLVED, ALREADYFIXED (but not in any deployments, or in the > UI) > and the resulting chatter slows down the XO/Sugar > considerably? > yes > Robot101 rwh > the latest versions of sugar and telepathy support using an XMPP > component called gadget > instead of the shared roster > Robot101: so gadget fixes this? > 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 > 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 > 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. > Robot101: what is the testing status of gadget? > 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) > Robot101: ok, will talk w/ them later today > gadget was always our plan, it just took us a while to get to > it > Robot101: by the way last year we tested ejabberd by streaming > your video talk on Telepathy to 80 XO's > 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 > bemasc: so it's still shared as in server-enforced mutual > visibility, just in smaller groups. > right, but from ejabberd's perspective, it's individual rosters > that's exactly how shared rosters always work > the client thread gets a copy of the same roster at sign in > oh? I thought there was a patch to ejabberd required. > yes, he's patched it to source the shared roster from moodle, > I'd imagine > martin seemed to say that he could use a totally stock ejabberd > 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 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 : > > > > 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 wrote: > > On Mon, 2009-03-09 at 17:51 +0000, 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] 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 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] 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 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] 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
