In message <4F2BF516.7070502 at pyther.net> Matthew Gyurgyik <pyther at pyther.net> wrote: > On 02/02/2012 04:18 PM, Alan Adams wrote: >> You've picked up one of the biggest problems with respect to deploying >> software to laptops. In general they are only turned on and connected >> to the network when the users want to work on them, and pushing >> software out to them in the background can cause problems. >> >> It is a particular problem in schools. A typical scenario is that of >> 30 children collecting laptops, taking them to the classroom and >> switching them on. At this point there is a lot of network traffic >> associated with Group Policies being deployed. As soon as the login >> window appears they enter their credentials, and there is another >> burst of GPO traffic. >> >> Somewhere in the middle of this wpkg starts downloading the 45MB MSI >> of Adobe Reader. Not content with that, it uninstalls the previous >> version, so it downloads that MSI as well. >> >> You've now got 30 laptops downloading 100MB of data each across, in >> the best case, 2 33Mb/sec wireless shared links. 30,000 mbits, through >> 66mbit/sec is 500 seconds, about ten minutes, ADDED to the normal >> startup and login time. Add the contention and retransmission overhead >> when the wireless gets saturated, and it can, and does, take an hour >> before the last pupil is logged in and ready to work. >> >> Primary school lessons are typically 25 minutes. >> >> Now I can see a way in the long term to reduce that. The wpkg script >> will copy the msi to a location on the hard drive, then run the >> msiexec command referencing the copy. No improvement this time round, >> but when it comes time to uninstall, it doesn't need to copy the msi >> again. That should give a factor two improvement. It will also help in >> deploying patch versions. To deploy 10.1.2 you deploy the 10.1.0 msi >> accompanied by the 10.1.2 msp. Combined, 65M. However the msi for >> 10.1.0 would already be on the computer. >> >> It also avoids the problem I've got at the moment. I deleted the Adobe >> reader 9.4.0 msi, then discovered some computers needed it for the >> uninstall when I deployed 10.1.2. (I don't know why they didn't get >> 10.0.0, 10.1.0 etc...) This means that I now cannot deploy 10.1.2 to >> those computers, because the uninstall part of the process fails. >> Setting the flag in 10.1.2 not to uninstall doesn't help, because it >> simply refuses to install as another version is present. >> >> I had to deploy Number Shark 4 last week. The msi is 450MB. Using >> wired connections it took around 15 minutes. Those using wireless, >> only 4 at a time, took almost an hour. Fortunately that school only >> has 30 laptops, so I managed to finish in a day. I had to pre-arrange >> that there would be no laptops available for the whole day though. >> >> i have been hoping I could use wpkg, running as a service, to allow >> deployment during lessons. Using AD deployment simply prevents the >> lesson from starting. (I only have one day every 3 weeks in each >> school, so doing it out of normal hours is generally not possible.) >> However the issues described above are making me think it still isn't >> going to work. >> > I appreciate your in-depth reply. It has brought up a lot a valid and > helpful points. We are dealing, currently, with 4 laptop carts each > containing 24 laptops. We have longer class periods (90 minutes). Just > to deploy Firefox (10MB) to a set of laptops would take 45 seconds > assuming ideal conditions (54Mbps). We have Wireless N access points, > but realistically we likely wouldn't come close to that with all 24 > clients connected. > From boot to login, it takes about 2-3 minutes. To add much more time > to the login process would be frowned upon. Maybe, the best solution in > this case would be to manually run wpkg from each machine to fetch new > updates/software. Alternatively, I might be able to create an AD user > that has a login script to call wscript. This way I could give said > username to a few staff to help with this process. The last is an interesting thought. Do you have staff who would be willing/able to help you out? Great if so. I'm heading down the "run at shutdown" route as the least-worst option. If I implement that I will be expecting lots of phone calls complaining that the computers won't shut down. Again the problem, as you no doubt find, is that 30+ computers do the same thing simultaneously, and wireless networks don't like that. -- Alan Adams, from Northamptonshire alan at adamshome.org.uk http://www.nckc.org.uk/ |