Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
On Wed, Mar 11, 2009 at 5:54 PM, John Watlington wrote: > If you aren't going to place school servers in the actual schools, > and insist on > centralizing them, the hardware recommended by Sameer is a good idea. +1 -- also, Dev Moharty's suggestion is good: run one XS for each school in your central location. If you have one big honking box, you could virtualise things (but I don't particularly recommend it). cheers, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ 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?
If you aren't going to place school servers in the actual schools, and insist on centralizing them, the hardware recommended by Sameer is a good idea. My argument has always been that you want local web caching and content, and that an XS shouldn't be that much more expensive than the above hardware. If you are willing to guarantee constant connectivity to a central office to support centralized servers, remotely maintaining the servers in the schools shouldn't be a problem. Cheers, wad On Mar 10, 2009, at 1:57 PM, Sameer Verma wrote: > On Tue, Mar 10, 2009 at 3:12 AM, Bryan Berry > wrote: >> On Mon, 2009-03-09 at 21:51 -0700, Sameer Verma wrote: >>> On Mon, Mar 9, 2009 at 7:04 PM, Bryan Berry >>> wrote: On Tue, 2009-03-10 at 09:58 +1300, Martin Langhoff wrote: > On Mon, Mar 9, 2009 at 12:11 AM, Bryan Berry > wrote: >> I am worried about the XO's and not the XS. > > Now you're starting to see what I've seen :-/ I also worry > about your > APs and networking infra -- to support 400 active users you'll > want at > least 8 APs. In more realistic terms, you'll probably need 12, > assuming a reasonably balanced load. 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? We are looking at about 100-150 students per school and connecting 3-4 schools to a central XS. > As I mentioned before... I am working on xs-0.6, with the > moodle-ejabberd magic. That's great, but our pilot starts in a month but that doesn't fit our timeline. I don't want to send out a completely new, untested XS into rural parts of Nepal. Do you have any other suggestions fo us? >>> >>> What if you had a small footprint box (like a soekris or >>> routerboard) >>> at the school that talks to APs on one end via a switch, and does >>> tunneling back to XS in a central location? That way you would >>> have a >>> fairly dumb tunnel unit at school (literally plug-and-play) and XS >>> management back at your central shop. >>> >>> Sameer >> >> Thanks for the suggestion Sameer. >> >> I don't really understand what benifits the soekris or routerboard >> adds >> in this situation? Can u pls explain further? >> > > The Soekris unit (say Soekris 4501 http://www.soekris.com/net4501.htm) > would sit at the school location talking to the APs via a switch on > one end and create a tunnel on the other end to your XS farm. The > tunnel runs over a VPN from school to XS farm. Both Soekris and > Routerboard have miniPCI slots that will take hardware accelerators > for VPN such as this one: http://www.soekris.com/vpn1401.htm so it is > possible to run VPNs on these boards. > > Soekris units are almost zero maintenance (no moving parts etc.) and > can also double up as APs. One thing to note: the hw VPN accelerator > support under Linux isn't very robust. I've used it with BSD > (http://m0n0.ch/wall/) and it works well. It will do IPSec VPN > tunnels. http://m0n0.ch/wall/features.php > > With a zero maintenance small footprint unit at the school (will run > with 12 V as well) and XS units at your "school server farm" you can > maintain the XS units locally and keep the school network running via > the VPN. > > The last time I suggested this, the -1 reasoning was that you would > need a good connection between the school and the XS farm. > http://lists.laptop.org/pipermail/server-devel/2008-October/ > 002244.html > > Sameer > -- > Dr. Sameer Verma, Ph.D. > Associate Professor of Information Systems > San Francisco State University > San Francisco CA 94132 USA > http://verma.sfsu.edu/ > http://opensource.sfsu.edu/ vpn.png>___ > 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?
On Tue, Mar 10, 2009 at 3:12 AM, Bryan Berry wrote: > On Mon, 2009-03-09 at 21:51 -0700, Sameer Verma wrote: >> On Mon, Mar 9, 2009 at 7:04 PM, Bryan Berry wrote: >> > On Tue, 2009-03-10 at 09:58 +1300, Martin Langhoff wrote: >> >> On Mon, Mar 9, 2009 at 12:11 AM, Bryan Berry wrote: >> >> > I am worried about the XO's and not the XS. >> >> >> >> Now you're starting to see what I've seen :-/ I also worry about your >> >> APs and networking infra -- to support 400 active users you'll want at >> >> least 8 APs. In more realistic terms, you'll probably need 12, >> >> assuming a reasonably balanced load. >> > >> > 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? >> > >> > We are looking at about 100-150 students per school and connecting 3-4 >> > schools to a central XS. >> > >> >> As I mentioned before... I am working on xs-0.6, with the >> >> moodle-ejabberd magic. >> > >> > That's great, but our pilot starts in a month but that doesn't fit our >> > timeline. I don't want to send out a completely new, untested XS into >> > rural parts of Nepal. >> > >> > Do you have any other suggestions fo us? >> > >> >> What if you had a small footprint box (like a soekris or routerboard) >> at the school that talks to APs on one end via a switch, and does >> tunneling back to XS in a central location? That way you would have a >> fairly dumb tunnel unit at school (literally plug-and-play) and XS >> management back at your central shop. >> >> Sameer > > Thanks for the suggestion Sameer. > > I don't really understand what benifits the soekris or routerboard adds > in this situation? Can u pls explain further? > The Soekris unit (say Soekris 4501 http://www.soekris.com/net4501.htm) would sit at the school location talking to the APs via a switch on one end and create a tunnel on the other end to your XS farm. The tunnel runs over a VPN from school to XS farm. Both Soekris and Routerboard have miniPCI slots that will take hardware accelerators for VPN such as this one: http://www.soekris.com/vpn1401.htm so it is possible to run VPNs on these boards. Soekris units are almost zero maintenance (no moving parts etc.) and can also double up as APs. One thing to note: the hw VPN accelerator support under Linux isn't very robust. I've used it with BSD (http://m0n0.ch/wall/) and it works well. It will do IPSec VPN tunnels. http://m0n0.ch/wall/features.php With a zero maintenance small footprint unit at the school (will run with 12 V as well) and XS units at your "school server farm" you can maintain the XS units locally and keep the school network running via the VPN. The last time I suggested this, the -1 reasoning was that you would need a good connection between the school and the XS farm. http://lists.laptop.org/pipermail/server-devel/2008-October/002244.html Sameer -- Dr. Sameer Verma, Ph.D. Associate Professor of Information Systems San Francisco State University San Francisco CA 94132 USA http://verma.sfsu.edu/ http://opensource.sfsu.edu/ <>___ 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?
On Tue, Mar 10, 2009 at 6:14 AM, Daniel Drake wrote: > 2009/3/10 Reuben K. Caron : >> Have you tried loading a different firmware on these, dd-wrt? > > No, but there are regulatory issues there and we won't be using them > in the schools...only used them because it was the only thing > available to run tests with. > > The exact model is Linksys WRT54Gv8. You'd think that after 8 > revisions and several years of developing these APs might support 34 > users, WDS, or running as a STA. nope! > There's a reason why Cisco bought them. Upgrade path! Squeeze from below, pull from above. http://www.linksystocisco.com/ Sameer > Daniel > ___ > 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] Serving 400+ students w/ a single central XS - ejabberd nightmare?
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 <mailto: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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
2009/3/10 Reuben K. Caron : > Have you tried loading a different firmware on these, dd-wrt? No, but there are regulatory issues there and we won't be using them in the schools...only used them because it was the only thing available to run tests with. The exact model is Linksys WRT54Gv8. You'd think that after 8 revisions and several years of developing these APs might support 34 users, WDS, or running as a STA. nope! Daniel ___ 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?
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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
On Mon, Mar 9, 2009 at 7:04 PM, Bryan Berry wrote: > On Tue, 2009-03-10 at 09:58 +1300, Martin Langhoff wrote: >> On Mon, Mar 9, 2009 at 12:11 AM, Bryan Berry wrote: >> > I am worried about the XO's and not the XS. >> >> Now you're starting to see what I've seen :-/ I also worry about your >> APs and networking infra -- to support 400 active users you'll want at >> least 8 APs. In more realistic terms, you'll probably need 12, >> assuming a reasonably balanced load. > > 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? > > We are looking at about 100-150 students per school and connecting 3-4 > schools to a central XS. > >> As I mentioned before... I am working on xs-0.6, with the >> moodle-ejabberd magic. > > That's great, but our pilot starts in a month but that doesn't fit our > timeline. I don't want to send out a completely new, untested XS into > rural parts of Nepal. > > Do you have any other suggestions fo us? > What if you had a small footprint box (like a soekris or routerboard) at the school that talks to APs on one end via a switch, and does tunneling back to XS in a central location? That way you would have a fairly dumb tunnel unit at school (literally plug-and-play) and XS management back at your central shop. Sameer -- Dr. Sameer Verma, Ph.D. Associate Professor of Information Systems San Francisco State University San Francisco CA 94132 USA http://verma.sfsu.edu/ http://opensource.sfsu.edu/ >> > This dell server has a dual-core Xeon 3.0 GHz processor and 2 GB RAM. >> > RAM was fine, beam only used 450 MB according to ps_mem.py >> >> Well, that's 1/4 of your RAM. You need to budget for apache/php, >> postgres, and squid. Right now the main problem is Squid. > > That was 450 MB during account creation. It dropped significantly > thereafter. I didn't provide much server stats last time because the XS > resource usage isn't a critical problem. > >> Thanks for the list below. Quite a few are about stuff I can't help >> with (roof leaks, power cords...) the others, I'm working on... > > That's the whole point of why I am telling you about such problems and > how they make a centralized XS easier for us to maintain. > > > -- > 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?
On Mon, 2009-03-09 at 22:36 -0400, 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. The linksys is WRT54G total crap. We don't use them. We have found that cheaper AP's do much better. We have good luck w/ random Taiwanese brands like Compex, Lantech, and AZTech. They have Atheros or RealTek chipsets > I haven't seen XO's bogged down by ejabberd chatter. Ran 75 today > while monitoring the TX/RX stats on the LAN interface on the XS and > was impressed at how low it was. > > Yes, the XOs run slow when you view a busy neighborhood view, but it's > fine as soon as you switch away. There was a bug where sugar updates > every icon on the neighborhood view 10 times every second when you are > on that screen (but only when you are on that screen), it's fixed for > 0.84. I saw it drop as well when I changed out of the Network View, but it still remained fairly high w/ 200 very active users, too high to keep me from launching EToys > > That's great, but our pilot starts in a month but that doesn't fit our > > timeline. I don't want to send out a completely new, untested XS into > > rural parts of Nepal. > > I tried and didn't get any feedback from XS usage in large > deployments, so we pretty much figured we'd send it into not-as-rural > paraguay and find out what happens (we don't really have any other > options!). > > Daniel I think that is because large deployments like Uruguay aren't using the XS and others like Mongolia don't have the technical expertise to monitor such things. That leaves new "large" deployments like Paraguay and Nepal in an unenviable position as pioneers. -- 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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
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. I haven't seen XO's bogged down by ejabberd chatter. Ran 75 today while monitoring the TX/RX stats on the LAN interface on the XS and was impressed at how low it was. Yes, the XOs run slow when you view a busy neighborhood view, but it's fine as soon as you switch away. There was a bug where sugar updates every icon on the neighborhood view 10 times every second when you are on that screen (but only when you are on that screen), it's fixed for 0.84. > That's great, but our pilot starts in a month but that doesn't fit our > timeline. I don't want to send out a completely new, untested XS into > rural parts of Nepal. I tried and didn't get any feedback from XS usage in large deployments, so we pretty much figured we'd send it into not-as-rural paraguay and find out what happens (we don't really have any other options!). Daniel ___ 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?
On Tue, 2009-03-10 at 09:58 +1300, Martin Langhoff wrote: > On Mon, Mar 9, 2009 at 12:11 AM, Bryan Berry wrote: > > I am worried about the XO's and not the XS. > > Now you're starting to see what I've seen :-/ I also worry about your > APs and networking infra -- to support 400 active users you'll want at > least 8 APs. In more realistic terms, you'll probably need 12, > assuming a reasonably balanced load. 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? We are looking at about 100-150 students per school and connecting 3-4 schools to a central XS. > As I mentioned before... I am working on xs-0.6, with the > moodle-ejabberd magic. That's great, but our pilot starts in a month but that doesn't fit our timeline. I don't want to send out a completely new, untested XS into rural parts of Nepal. Do you have any other suggestions fo us? > > This dell server has a dual-core Xeon 3.0 GHz processor and 2 GB RAM. > > RAM was fine, beam only used 450 MB according to ps_mem.py > > Well, that's 1/4 of your RAM. You need to budget for apache/php, > postgres, and squid. Right now the main problem is Squid. That was 450 MB during account creation. It dropped significantly thereafter. I didn't provide much server stats last time because the XS resource usage isn't a critical problem. > Thanks for the list below. Quite a few are about stuff I can't help > with (roof leaks, power cords...) the others, I'm working on... That's the whole point of why I am telling you about such problems and how they make a centralized XS easier for us to maintain. -- 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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
On Mon, Mar 9, 2009 at 12:11 AM, Bryan Berry wrote: > I am worried about the XO's and not the XS. Now you're starting to see what I've seen :-/ I also worry about your APs and networking infra -- to support 400 active users you'll want at least 8 APs. In more realistic terms, you'll probably need 12, assuming a reasonably balanced load. As I mentioned before... I am working on xs-0.6, with the moodle-ejabberd magic. > This dell server has a dual-core Xeon 3.0 GHz processor and 2 GB RAM. > RAM was fine, beam only used 450 MB according to ps_mem.py Well, that's 1/4 of your RAM. You need to budget for apache/php, postgres, and squid. Right now the main problem is Squid. Thanks for the list below. Quite a few are about stuff I can't help with (roof leaks, power cords...) the others, I'm working on... cheers, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ 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] Serving 400+ students w/ a single central XS - ejabberd nightmare?
On Sun, 2009-03-08 at 22:36 +1300, Martin Langhoff wrote: > On Sun, Mar 8, 2009 at 7:52 PM, Bryan Berry wrote: > > 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" > > Give ejabberd enough RAM and it won't be a problem. The rest of your > infrastructure will, however. I am worried about the XO's and not the XS. I used the hyperactivity program and got some unscientific results. I simulated 200 users using the schoolserver constantly. The CPU of the XS was very busy, staying near 100% usage during the account creation period and then it leveled off. I didn't monitor it very closely after that b/c ejabberd is not my chief concern This dell server has a dual-core Xeon 3.0 GHz processor and 2 GB RAM. RAM was fine, beam only used 450 MB according to ps_mem.py sudo ./hyperactivity.py gabble schoolserver.schoolnet.gov.np 200 I ran hyperactivity from my regular dell laptop My XO showed 200 users in the Network View and became very sluggish. Top showed that 30-40% of CPU was taken up w/ handling the sugar-shell, the program which manages the Network View. The dbusdaemon was using roughly 15-20% of the CPU. I tried to launch one our E-Paath flash activities and it hung displaying the error message "Unresponsive script". I tried to launch EToys and it failed as well. > > The XS is quite a complicated ensemble of software having an XS at every > > school magnifies the administration work. > > What admin work do you foresee on the XS? * Making sure that ejabberd keeps running * Making sure that the school doesn't have roof leak directly above the XS * Making sure the schools doesn't remove the power cord and use it for something else * Make sure the school doesn't repurpose the UPS for the XS for charging cell phones * make sure the XS doesn't get zapped by a sudden power surge * Making sure it is there 3 months later * Make sure that dansguardian, squid, dhcp stay up week after week We don't have any problem gettting the kids to take care of the XO's but we have a Hell of a time making sure they take care of the XS > > 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. > > Good point. I've been building everything with daily "poweroffs" in > mind and every component should handle it. But haven't field-tested... Sadly, no one has and this is one of my chief concerns > > we can provide that (RAM) > > Have you go the 4GB barrier in mind? Past 4GB we get into all sorts of > problems. You'll need a 64-bit machine, and you'll have to convince me > or someone else to build a 64-bit XS iso rather than the vanilla > 32-bit we're using now. > > > We have a relatively low latency connection b/w the schools and the XS. > > Low latency, high bandwidth and everyone in the same netblock? No > routers in the middle. That's what the XS assumes, in any case. > > > the conclusion that Nepal has different requirements than some of the > > other pilot schools. > > Everybody is a little bit special. By deviating from how the XS is > designed to be deployed, you will add mgmt work to workaround whatever > gotchas. -- 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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
On Sun, Mar 8, 2009 at 10:36 PM, Martin Langhoff wrote: > And you make the Nepal deployment less useful to me too :-( -- you'll > probably have to setup routing and other things on the XS so that > you'll have to carefully debug it to ensure it's not your network > setup before reporting it here. Clear as mud. What I lamenting is that _before reporting a network-related bug_ you'll have to factor out your local network oddities. cheers, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ 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?
On Sun, Mar 8, 2009 at 7:52 PM, Bryan Berry wrote: > 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" Give ejabberd enough RAM and it won't be a problem. The rest of your infrastructure will, however. > The XS is quite a complicated ensemble of software having an XS at every > school magnifies the administration work. What admin work do you foresee on the XS? > 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. Good point. I've been building everything with daily "poweroffs" in mind and every component should handle it. But haven't field-tested... > we can provide that (RAM) Have you go the 4GB barrier in mind? Past 4GB we get into all sorts of problems. You'll need a 64-bit machine, and you'll have to convince me or someone else to build a 64-bit XS iso rather than the vanilla 32-bit we're using now. > We have a relatively low latency connection b/w the schools and the XS. Low latency, high bandwidth and everyone in the same netblock? No routers in the middle. That's what the XS assumes, in any case. > the conclusion that Nepal has different requirements than some of the > other pilot schools. Everybody is a little bit special. By deviating from how the XS is designed to be deployed, you will add mgmt work to workaround whatever gotchas. And you make the Nepal deployment less useful to me too :-( -- you'll probably have to setup routing and other things on the XS so that you'll have to carefully debug it to ensure it's not your network setup before reporting it here. Naturally, it's your call to make. It looks to me like you're getting into a tricky space with routing setup, potential 64-bit OS and other curly issues. If the administrative workload you expect on the XS is really big and tricky, then I'd agree with you... (... but then, I'd like to know what's the big and tricky admin work on the XS? my design principle that it should be super-low-maintenance... ) cheers, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ 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?
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
Re: [Server-devel] Serving 400+ students w/ a single central XS - ejabberd nightmare?
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. - 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 - 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... hth, m -- martin.langh...@gmail.com mar...@laptop.org -- School Server Architect - ask interesting questions - don't get distracted with shiny stuff - working code first - http://wiki.laptop.org/go/User:Martinlanghoff ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
