Hey James, I don't envy you on this one, but I think you're on a good track.
Regarding the original question of how to tell if a particular PC is connected or not, can the router's DHCP server be configured to give out a fixed/static IP address according to the client's MAC address? Some routers (DHCP servers) can, some cannot. If you can dish out fixed addresses to the PCs (still via DHCP), it'd be a simple matter to ping them to see if they're connected or not. Might be worth switching to a router (DD-WRT comes to mind) which can do this in order to keep things simple.
Best of luck on your project. I'd be interested to know how it turns out for you.
-- -Eric 'shubes' On 01/06/2012 05:23 PM, James Dugger wrote:
Lisa, Thanks for the code snippets and the direction. Kevin, I anticipated that I might get this response and I appreciate the recommendations. I will look into backupPC. There are some pretty narrow constraints that I am working with that have lead me to this direction. 1. This project is for a business that has outgrown the home offices of 5 people into an established office location. They all use laptops that are currently not apart of any network. I use the term LAN only in the sense that their router is providing wireless access and the ability (now that they are are centrally located) to connect to each other. 2. These users have little if any understanding or experience with connecting or working in a network environment where they share files from a server, and do not want to. 3. They are averse to spending any additional resources to formalize a LAN. 4. They still work from home occasionally and each persons tasks are such the they don't need to share files very much. 5. The only reason they have been convinced that they need a central backup system is because of a recent scare to a lost directory on one of their laptops. 6. They will most likely not initiate a backup from there laptops and given personal use of the laptops if I install a system that works from there laptop there is very little guarantee that they won't inadvertently shut it down (accidentally). Sounds like a security nightmare. At this stage I am only providing a NAS and a backup solution and trying to make it as locked down as I can. With the parameters above I have built a NAS backup server that basically works in the background with only the following tasks 1. Manage a 4 TB software RAID 10 configuration of disks 2. Provide a file server environment using Samba 3. Provide a symlinked share folder (named the same as there My Docs) folder to access backups if needed 3. Webmin and Openssh for admin access (server is headless) 4. Provide backup script using rsync and cron to create a rotating incremental backup 5. Perform all this on the server side - I have no control administratively to do much configuring or lock down the laptops. 6. Create a log file of backups and notify me by email of any viruses, failures, or crashes. All that aside, I have looked at several backup "programs" that are out there and as I have delved into them more and more I am finding that many of them are simply scripts written in Perl or Python or bash to run rsync or a version of it. I personally think that it is overkill to load a program that is designed to do 13 things when I need it to only to do 3. I have in the past attempted to configure rsnapshot for this very purpose only to be disappointing in my limitations on naming files, or how the backup works, or a combination of all of these. I find it ironic that I should spend time learning first how backupPC works than learn how to configure it to do something that you can have rsync do in no more than a handful of lines in a bash script. Besides I am trying to leverage my time learning more about Linux, bash scripting, and the standardized offerings in most distros (rsync). I spent 20 years "finding" software in M$ world to make sure that I didn't have to learn anything about Windows servers. As far as the load on the network, all of the laptops and router have gigabit NIC's. Most of the work that they do is actually updating their eCommerce site which is hosted offsite. There are incidental daily text files and image files optimized (sized) for web that are the primary items being backup. rsync should be able by itself to snapshot incremental file changes in all of their directories after the initial full backup in seconds simultaneously. At any rate the only real load is on the backup server which should not have any other active writes to the drives from users. Despite this I do appreciate the insights of any here. I am not putting down any programs, and if this was a more standardized network with more band usage, server services, and user account management I would check myself in to the nearest loony bin before trying to "reinvent the wheel". On Fri, Jan 6, 2012 at 11:01 AM, Kevin Fries <ke...@fries-biro.com <mailto:ke...@fries-biro.com>> wrote: On Fri, 2012-01-06 at 08:49 -0700, Lisa Kachold wrote: > Hi Kevin: > On Fri, Jan 6, 2012 at 8:26 AM, Kevin Fries <ke...@fries-biro.com <mailto:ke...@fries-biro.com>> > wrote: > Just out of curiosity... > Is there a specific use case you are using to explain why you > are reinventing the wheel? > Much of our discussion with scripting and systems use is like "Hello > World". > > http://backuppc.sourceforge.net/faq/BackupPC.html > It would help to know exactly what you are trying to achieve > that BackupPC can't handle so we can find you a better > solution. > Great solution: but he is trying to identify all connected samba > shares from Windows7 machines only on a DHCP network. > Kevin Lisa, That was not what I got out of the OP's original message at all. I read that he is trying to poll Samba to see which Windows based laptops are connected, then trying to do a rsync to back up those laptops. Seems like a lot of work, and a lot of maintenance for something that is already built. It just takes reversing your logic a little. His original idea would cause all backups to occur at a fixed time (since it was created from the same bash script), and rsync the Windows boxes connected at that time. This solution has a few huge holes that are not addressed: All machines are backed up at once, adding a lot of stress on the network within a short time period. Second, What if Laptop A does not check in at the given time for 6 months? How would he know? Third, this only keeps a single backup of a file, not a revisioned version of the file. And Fourth, These are windows users, how do they initiate a restore of a file? The solution I proposed, uses polling and last backed markers to manage backups. If a machine has not been backed up in one week, a notice can be sent to the admin notifying them of this situation. It also handles revisioned backups... If a file changes, then changes again, that first change is not lost until the backup system rotates files off. I used to use this product specifically in a Windows desktop (Linux Server) environment, with daily incremental backup, full backup every 30 days, three backup archive. So, users had 90 days of backups at their disposal. And finally, users initiated their own restores. Including if needed full system restores. For backup of laptops, just increase the polling time to improve the chance of catching them online. It will only back them up once per configured period. So, if you say back up daily, and it polls 10 times per day, it will not matter that the machine is there all 10 periods or only one, it will still only back up once. And this solution includes a throttling option that will prevent your network from getting saturated. The OP never mentioned anything about Windows Shares that I saw. He mentioned trying to use Samba for machine detection to then initiate an rsync for backup. Unless there is some underlying reason that I did not understand, there are free, FOSS solutions out there that will do a far superior job to what he was trying to do. That is why I was asking what I was asking... What situation are you trying to solve that existing software has not already solved. Kevin --------------------------------------------------- PLUG-discuss mailing list - PLUG-discuss@lists.plug.phoenix.az.us <mailto:PLUG-discuss@lists.plug.phoenix.az.us> To subscribe, unsubscribe, or to change your mail settings: http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss -- James
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