using unison for robust Linux, OSX, and Windows file syncronization November 30, 2008
Posted by eddiedunn in Uncategorized.add a comment
I have been struggling with the perfect backup for my home network, well I say backup it is really more of a hot sync to my drobo. This drobo is connected to my CentOS 5.2 box. The machine I am trying to backup is my windows xp desktop with all my families photos and other important files.
The first attempt at this was to simply create a samba share on my linux box of the backup directory on the drobo, mount the share by way of a mapped network drive and run robocopy with the mirror options to sync the backup files on the xp machine with the drobo. This absolutely killed the responsiveness of my linux box. I am really not sure if one thing was to blame for this but a culmination of disk ( slow usb drobo) and network i/o waits and the shear amount of data that was being processed made even a normal run, which by my calculation should be finished in hours or even minutes in terms of data transfer, take multiple days. I started reading around and saw what some people were doing when trying to sync files across windows and linux. I saw that some were using cygwin and running rsync. This seemed like a pottentially good solution but I really could not justify putting cygwin on my windows box just for rsync. I then came across unison.
Unison is a great little tool that allows you to perform 2-way syncs of files and directories across Mac, Windows and Linux platforms.
I wanted to let the linux server initiate the backup mainly because it is always on and many times the desktop is turned off during the backup window (more on this). I chose to also use the socket method and restrict that port to my linux box ip (note this is a trusted network with no wireless). This meant I needed to run unison in socket server mode by the -socket <port number> parameters as a windows service that would automatically start at boot. To accomplish this I grabbed the text windows exe version of unison and placed it in path. I then installed it as a service using microsoft’s instructions. Note in this context the Application value will be
“<fullPathToUnison_exe> -socket <port number>”.
I simply installed the application on CentOS from the rpmforge repository and invoked it using cron as follows
unison socket://<host>:<port>/c:/Documents\ and\ Settings/user /mnt/drobo/home/user
Obviously your paths will vary…
I got the following from someone somewhere along the way. Here are the default settings on my linux unison account that runs the backups and are good in general for using unison with windows
——————————————-
# Helps out a lot on Windows
fastcheck = true
# place new files at the top of the list
sortnewfirst = true
# turn on ssh compression
rshargs = -C
ignore = Name Thumbs.db
ignore = Name *~
ignore = Name *.tmp
———————————————-
Note I am purposely leaving out important points about this tool especially how it deals with conflicts if you do not fully understand what you are doing. I am still learning these myself 
The best advice I can offer is to read the docs for the finer points of the tool.
Another piece of the puzzle is using a magic packet generator to trigger the wake on lan function of the windows machine to wake up the windows machine in the case that it is powered off at the beginning of a backup window. I used the linux tool wol for this. I found a great guide on remote wakeup and using this tool. Note you must enable both in the bios on the motherboard and in the driver settings in the os. (setting found and changed using ethtool in linux and in the power management tab of the network card driver in device manager windows).
This setup also provides the luxury of being able to add files to the “backup” on the linux/drobo side and have them replicate back to my windows desktop. This could get even more hairy with respect to conflict resolution and I cant right off think of an occasion I might actually use that but hey, its cool knowing I can
Blogging in the Classroom June 11, 2008
Posted by eddiedunn in Education.Tags: educational technology
2 comments
A Weblog or “blog” is a website consisting of many articles usually listed in reverse chronological order. These articles are most commonly textual in content but can also include images, sound, and even video. There are many Weblog products, some of them are free and others require payment for use. We are going to highlight WordPress, one of the more popular free products.
Getting started is quite simple. All one needs to do is have a working email address and click on the following link:
WordPress Signup
Once the form is completed and submitted you will need to activate the account. This is done by checking your email and clicking the special activation link contained in an email from WordPress. Now you are ready to start blogging!
WordPress Lessons
Options for instructors using blogs:
- Content-related blog as professional practice
- Networking and personal knowledge sharing
- Instructional tips for students
- Course announcements and readings
- Annotated links
- Knowledge management
Options for students using blogs in your courses include:
- Reflective or writing journals
- Knowledge management
- Assignment submission and review
- Dialogue for groupwork
- E-portfolios
- Share course-related resources
“Henry Farrell identifies five major uses for blogs in education:
1. Teachers use blogs to replace the standard class Web page. Instructors post class times and rules, assignment notifications, suggested readings, and exercises. Aside from the ordering of material by date, students would find nothing unusual in this use of the blog. The instructor, however, finds that the use of blogging software makes this previously odious chore much simpler.
2. Instructors begin to link to Internet items that relate to their course. Mesa Community College’s Rick Effland, for example, maintains a blog to pass along links and comments about topics in archaeology.15 Though Mesa’s archaeology Web pages have been around since 1995, blogging allows Effland to write what are in essence short essays directed specifically toward his students. Effland’s entries are not mere annotations of interesting links. They effectively model his approach and interest in archaeology for his students.
3. Blogs are used to organize in-class discussions. At the State University of New York at Buffalo, for example, Alexander Halavais added a blog to his media law class of about 180 students. Course credit was awarded for online discussion, with topics ranging from the First Amendment to libel to Irish law reform. As the course wound down with a discussion of nude bikers, Halavais questioned whether he would continue the blog the following year because of the workload, but students were enthusiastic in their comments
Mireille Guay, an instructor at St-Joseph, notes: “The conversation possible on the weblog is also an amazing tool to develop our community of learners. The students get to know each other better by visiting and reading blogs from other students. They discover, in a non-threatening way, their similarities and differences. The student who usually talks very loud in the classroom and the student who is very timid have the same writing space to voice their opinion. It puts students in a situation of equity.”
4. Some instructors are using blogs to organize class seminars and to provide summaries of readings. Used in this way, the blogs become “group blogs”—that is, individual blogs authored by a group of people. Farrell notes: “It becomes much easier for the professor and students to access the readings for a particular week—and if you make sure that people are organized about how they do it, the summaries will effectively file themselves.”
5. Students may be asked to write their own blogs as part of their course grade. Educational Technologist Lane Dunlop wrote about one class at Cornell College: “Each day the students read a chunk of a book and post two paragraphs of their thoughts on the reading.” In another class, French 304, students were given a similar exercise. Using a French-language blogging service called Monblogue, Molly, a business student, posted a few paragraphs every day.”
references:
http://www.pembinatrails.ca/program/technology/uses_of_blogs_in_education.htm
http://awd.cl.uh.edu/blog/
