On 9/17/07, Oren Beck orenbeck@gmail.com wrote:
Concise statement of a non-trivial larger concept is to have a Linux server make timed backups of several windows systems in a zero user interaction format- and be able to remote restore those boxes equally "no user assist" required.
Define "zero user interaction format" and "no user assist", which you've already put in quotes.. Do these mean that we're allowed one or more "administrators" as opposed to "users" to install and configure the system on the backup server(s) and Windows systems, or what, exactly?
These periodic "Make it simple enough for the dummies!" exercises try my patience. There is a minimum amount of complexity involved in a backup system that can't be avoided. If nothing else, when the Windows side runs, if it does not pop up some message confirming that the backup was successful, the "No news is good news" trap is set. A failure of the backup software to run would be interpreted by the users as "everything is OK", which it isn't.
I speak from painful experience here.
Another painful fact is that backup software running under Windows seems to be unable to back up files in use. I'm not sure why this is, but I look at backup logs and see it all the time. The first lesson in the Tao of Backup (http://taobackup.com/coverage.html) teaches that every file must be backed up. As Windows typically has open hundreds or even thousands of files, precisely those most important for proper functioning, this is a huge issue.
The backup software we use for *nix backs up every single file on all mounted filesystems (with such exceptions as we may set up in a config file). It produces bootable media (CD or pair of diskettes) with which one can install a brand new hard drive, boot the system, and reload everything from tape, resulting in a fully-functional system. We don't have trouble backing up all the files under *nix, because the software doesn't try to open files in an exclusive mode.
I assume that the people who write the backup software aren't complete idiots, so that makes me think there may be a technical reason why Windows doesn't allow them to do a better job of it. It may be necessary to have software that writes an entry to the Registry, forces a reboot of the server, and then runs in exclusive mode during the boot. I've seen programs like Partition Magic do this to solve exclusive access problems. A slightly-different approach might modify boot.ini (or whatever the Vista equivalent is) so that Windows doesn't even boot at all that time, but instead loads a Linux kernel to do the backup (and then reset boot.ini to load Windows next time). Or the Windows loader could be chained off grub.
A lot of such details depend on the BIOS limitations. The proverbial "Make it unhappen" CD, which boots into Linux, checks the backup server(s) to see what's available (which might require some creative use of bootp) and offers complete images from which to restore a system. But you still will have choices to make. Someone has to decide how many images per machine to retain, then at restore time decide which one to use....