<font color="#000000"><font face="tahoma,sans-serif">You need to either have a local repository or download from the internet again. I've used 'apt-mirror' in the past to maintain a local cache but that was when I was building local systems with a minimal Debian installer. I don't even know if the standard Ubuntu installer can load off a local cache. (I guess the process is to do the install "without updates", change your sources.list files, then upgrade from the cache.)<br>
</font></font><div><div><div><font class="Apple-style-span" face="tahoma, sans-serif"><br></font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">It's also worth remembering that the specific versions of your packages may not be available when you need to restore your system. This is usually a good thing since more recent versions have a shot at preventing whatever caused you to lose your system in the first place (e.g., closing vulnerabilities) but some people may need to restore the system exactly.</font></div>
<div><font class="Apple-style-span" face="tahoma, sans-serif"><br></font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">On checksums - I checked my system and almost none of the conffiles have checksums. (In fact that may be against packaging standards - I would have to check.) That's a bummer since it means that there's no easy way of seeing what's changed unless you peek into the .deb file. There are some deb tools that can do this but since I can do it programmatically I usually just did that.</font></div>
<div><font class="Apple-style-span" face="tahoma, sans-serif"><br></font></div><div><font class="Apple-style-span" face="tahoma, sans-serif">The 'monster diff' is just a comment on the number of files involved. What I actually did create two lists, one generated by walking the filesystem and the other generated by concatenating all of the *.files and *.md5sums metadata and then comparing them. I did this programmatically but you could also create actual files, sort them, and then run a diff on them. IIRC I typically had over 70k files.</font></div>
<div><font class="Apple-style-span" face="tahoma, sans-serif"><br></font></div><div><div class="gmail_quote">On Fri, Oct 28, 2011 at 3:33 AM, Gaurav Saxena <span dir="ltr"><<a href="mailto:grvsaxena419@gmail.com">grvsaxena419@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">Hello all<br><br><div class="gmail_quote"><div class="im">On Fri, Oct 7, 2011 at 4:45 AM, Bear Giles <span dir="ltr"><<a href="mailto:bgiles@coyotesong.com" target="_blank">bgiles@coyotesong.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<font color="#000000"><font face="tahoma,sans-serif">I've written a few prototypes and this comes down to four issues. Some of the details below are debian/ubuntu-specific but the same concepts will apply to redhat.<br>
</font></font><div><font face="tahoma, sans-serif"><br></font></div><div><font face="tahoma, sans-serif">1. User data (/home) must be backed up explicitly. (ditto server data on servers).</font></div>
<div><font face="tahoma, sans-serif"><br></font></div><div><font face="tahoma, sans-serif">2. Packages should NOT be backed up. All you need is the package name and version. Reinstall from .deb and .rpm if necessary since this way you're sure that you never restore compromised files.</font></div>
</blockquote></div><div>But it might be possible that the package files are not available on the system. That means for all the packages installed the .deb files need to be downloaded from the internet for restore purpose ?</div>
<div class="im">
<div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><font face="tahoma, sans-serif"><br></font></div><div><font face="tahoma, sans-serif">3. Configuration data (/etc) must be backed up explicitly. This is tricky because backing up the entire directory will cause its own problems. Worse, some applications keep their configuration files elsewhere. The best solution I've found is to scan the package metadata to identify configuration files and to only save those with a different checksum than the standard file.</font></div>
</blockquote></div><div>Ok. Nice idea indeed , but is there checksum associated with the files in the package ? Or that can be calculated at the time of restore ? What you say ?</div><div class="im"><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><font face="tahoma, sans-serif"><br></font></div><div><font face="tahoma, sans-serif">4. Local files. Ideally everyone would keep these files under /usr/local and /opt but that's rarely the case. The best solution I've found is to scan the debian package metadata and do a monster diff between what's on the filesystem under /bin, /sbin, /usr and (chunks of) /var with what's in the metadata.</font></div>
</blockquote></div><div>Could you suggest me some way of scanning the debian package metadata without actually downloading the packages? and how to this monster diff ? </div><div class="im"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><font face="tahoma, sans-serif"><br></font></div><div><font face="tahoma, sans-serif">It's worth noting that the last item isn't that hard if you have a strict security policy that everything under those directories MUST be in a package. It's deleted without a second thought if it's not. You can still do everything you could before, you just need to create a local package for it.</font></div>
<div><div class="gmail_quote"><br></div><div class="gmail_quote">So what do you do with this? The best solution, which I haven't implemented yet, is to handle #2 and #3 with autogenerated packages. You set up one or more local packages that will install the right software and then overwrite the configuration files. You can fit everything, including original package archive, on a single DVD.</div>
</div></blockquote></div><div>Could you please tell some detail about autogenerated packages ? Like if we have a list of packages installed on the system, We need to reinstall those all softwares and remove those which are installed after the restore point? </div>
<div class="im">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
<div class="gmail_quote"><br></div><div class="gmail_quote">BTW Debian has a C++ interface to the package metadata. I've never used it - I find it easier to just scan the metadata directory myself. There's also hooks that will allow your application to be called at each step during a package installation or removal. You could, in theory, keep your snapshots current to the last minute that way.</div>
</div></blockquote></div><div>So whenever a package is installed or removed I will update my backup according to that ? By reading package metadata determine which files are changed by that package and update those files in the backup ? </div>
<div><div></div><div class="h5">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div></div><div>
<div class="gmail_quote"><br></div><div class="gmail_quote"><br></div><div class="gmail_quote">On Fri, Sep 30, 2011 at 12:01 AM, Gaurav Saxena <span dir="ltr"><<a href="mailto:grvsaxena419@gmail.com" target="_blank">grvsaxena419@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="gmail_quote">Hello Aaron <div>Thanks a lot for your quick reply.<br><br><div class="gmail_quote"><div>On Fri, Sep 30, 2011 at 10:03 AM, Aaron C. de Bruyn <span dir="ltr"><<a href="mailto:aaron@heyaaron.com" target="_blank">aaron@heyaaron.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">In Windows, the ability to snapshot is built into the filesystem.<br>
In Linux, you must be running a filesystem that supports snapshots. I<br>
know LVM supports snapshotting and I believe BRTFS has support, but<br>
other than that I'm not sure.<br>
<br></blockquote></div><div>Yes I read the logic behind windows system restore. But I think we can take some other approach for this, that will be better as all users won't be able to spare an extra partition formatted brtfs. </div>
<div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Basically, your program would have to check the file system that is<br>
used on the computer (remember Linux can have many types of file<br>
systems mounted at the same time), then (in the case of LVM) make sure<br>
there's enough free space to snapshot, and finally take the snapshot.<br>
<br></blockquote></div><div>Ok. Do I have to snapshot the whole system partition / important system files to the brtfs partition ?</div><div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
When the snapshots start filling up, you would either need to delete<br>
them or detect the low space and resize them.<br>
<br>
In my personal opinion, snapshotting in Linux is currently a pain in<br>
the rear. It sounds like BTRFS could change that, but it's still a<br>
ways off.<br>
<br></blockquote></div><div>Ok. I will try another approach that will be better as suggested by people here.</div><div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
-A<div><div></div><div><br>
<div><div></div><div><br>
On Thu, Sep 29, 2011 at 21:00, Gaurav Saxena <<a href="mailto:grvsaxena419@gmail.com" target="_blank">grvsaxena419@gmail.com</a>> wrote:<br>
> Hello all,<br>
> I want to write a windows system restore like program for ubuntu , which<br>
> will have options for creating restore points for the system and then<br>
> restoring it back to that point. Also I will as an extension provide support<br>
> for older version of a file as is in windows currently. I need your help to<br>
> find how to start with this in ubuntu. I know that I have to snapshot the<br>
> system when creating a restore point and then restore it. I need some<br>
> starting pointers so that I can start doing this work. Also if this has<br>
> already been done please inform me. I got this idea from<br>
> <a href="https://wiki.ubuntu.com/SystemRestore" target="_blank">https://wiki.ubuntu.com/SystemRestore</a>.<br>
> --<br>
> Thanks and Regards ,<br>
> Gaurav<br>
><br>
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</blockquote></div></div><div><font color="#888888"><br><br clear="all"><div><br></div>-- <br>Thanks and Regards ,<br>Gaurav<br>
</font></div></div>
</div><div><div></div><div><br><br clear="all"><div><br></div>-- <br>Thanks and Regards ,<br>Gaurav<br>
</div></div><br>--<br>
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<br></blockquote></div><br></div></div></div>
</blockquote></div></div></div><div><div></div><div class="h5"><br><br clear="all"><div><br></div>-- <br>Thanks and Regards ,<br>Gaurav<br>
</div></div></blockquote></div><br></div></div></div>