linux.gentoo.user

Dan Farrell wrote:
> On Sat, 1 Mar 2008 02:04:31 -0500
> "Ritesh Kumar" wrote:
>
>
>> On Fri, Feb 29, 2008 at 8:23 PM, maxim wexler
>> wrote:
>>
>>
>>>> Doesn't Ghost work with Ext3? What can I do to
>>>> recover my system without
>>>> reinstalling from scratch?
>>>>
>>>>
>>> I've had success with #dd if=
>>> of= bs=
>>>
>>>
>>>
>> Is there a reason why you backup the filesystem along with the data
>> on it? I do only minor backups... but even for anything major I would
>> use a tool like tar or rsync and drop the filesystem metadata
>> entirely.
>>
>> Also directly reading from the block device is hazardous unless you
>> umount (or mount as readonly) the filesystem in question. This is
>> because, the filesystem may not keep all the data synced to the disk
>> at all points in time.
>>
>
> not that i'd recommend it for production systems, but you could mount
> with the 'sync' option to help with this.
>
>
Even mounting sync is not safe, if you want to use dd for a backup then
boot from the live cd to backup everything. Otherwise using these
methods is risking a backup that once restored, does not work - not good
for the blood pressure...

If you want to back the system up while it is running (in particular /),
then you need to use a tool that understands how to create a backup
image that is valid (i.e will boot) - something like xfsdump, dumpe2fs
etc or smart tar/dump based tools like Amanda.

I would recommend using one of the dump tools for /boot, /, /usr, /var
*at least*. I've had the misfortune of helping many people restore their
broken Linux and Freebsd systems... and the only backups I've never had
issues with have been the *dump variety. They are a little unfriendly at
first, but they work.

regards

Mark




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