Why not tar, instead fsarchiver.

Please ask questions here if you are not familiar with fsarchiver
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tuipveus
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Joined: Thu May 14, 2009 7:02 pm

Why not tar, instead fsarchiver.

Post by tuipveus » Sun May 17, 2009 4:13 pm

I don't get it. What are the benefits of using fsarchiver instead tar + compression-program? Checksums are one thing, but I can't see any other.

Fsarchiver can't handle partitiontable, so why should I use it? I have used system rescue cd with partimage for years, without problems. I have copied partitiontables with sfdisk and dd.

Thing what people really need is rescuecd which you can use to copy whole disk, instead separate copy of filesystem1, fs2, fs3 etc.etc. and another copy of the partition table.

After hearing first time about fsarchiver, I was happy to notice that I restore the fs to smaller disk. But after using fsarchiver, I noticed that I was not able to restart the system without installing grub again (even when archived/restored to same size of disk). So I think it doesn't make difference for me: I can use either fsarchiver or tar to copy stuff. I can make filesystems manually, instead using fsarchiver.

Keep up the good work, but please hear my critics.

Does someone has ideas, why I got message "GRUB GRUB GRUB" after restoring system? Before restoring fs with fsarchiver, I restored first 512 bytes with dd. Partitiontable has/had only 4 primary partitions.

admin
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Post by admin » Sun May 17, 2009 7:27 pm

fsarchiver is not just like tar, because tar won't preserve all the file attributes (especially xattr) which will make Redhat with selinux enabled unbootable.

Also you have to restore the filesystem attributes (label, uuid) because many distributions are using these things to identify the root filesystem in grub. So it's another thing to do by hand.

If you make a 5GB tar.gz file and you have a corruption at the beginning of your archive, you will loose all your data. With fsarchiver, it will just skip the bad file. All the files in an fsarchiver archive are checksummed using md5.

tar cannot preserve the windows file attributes, fsarchiver can save and restore ntfs partitions and it preserves all the files attributes including windows permissions.

tar does not provide support for encrypted archives. fsarchier can handle multiple filesystems per archive.

This project is only six months old, I have many plans in mind but only my spare time to work on this project. The ability to recreate partitions using libparted and the GUI are the next features I will develop, as well as support for grub.

tuipveus
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Joined: Thu May 14, 2009 7:02 pm

Post by tuipveus » Sun May 17, 2009 8:35 pm

fdupoux wrote:fsarchiver is not just like tar, because tar won't preserve all the file attributes (especially xattr) which will make Redhat with selinux enabled unbootable.

Also you have to restore the filesystem attributes (label, uuid) because many distributions are using these things to identify the root filesystem in grub. So it's another thing to do by hand.
Both filesystem attributes and label,uuid are good reasons to use fsarchiver as well as protection against corruption and encrypted files. I really hope that you can develop fileformat, which can be expanded later on with new features, such as compression algorithms, partition tables etc.
The ability to recreate partitions using libparted and the GUI are the next features I will develop, as well as support for grub.
Sounds great! Partimage gui was plain, simple, and easy to use, but it was/is lack of copying whole disk, which was featured with other parties projects as clonezilla. Clonezilla userinterface and jumping from menu to another was however quite confusing for me.

Things what I hope from fsarchiver are:
1) stability. Backups are always something what you have to be able to trust.
2) support to handle diskdevices and undelying partitions.
3) copy disk without reinstallation of grub (copying grub)
4) possibility to identify disks (from menus), not just by their device nam (sda), but also with physical name and serial number: smartctl --all /dev/hda |grep "Device Model"

Keep up the good work.

tuipveus
Posts: 44
Joined: Thu May 14, 2009 7:02 pm

Post by tuipveus » Sun May 17, 2009 9:29 pm

It would be also good if it is possible to save disk-size, partition-size and number to fsa-file.

This way you can notice later on, if you are restoring filesystems to bigger disk and expand partitions way you want before restoring filesystems. This way you also can give warning people, if they are overwriting wrong (different than original) disk with fs-image.

admin
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Post by admin » Mon May 18, 2009 6:52 am

I think the file format will be flexible enough to add new info like that (partition size, primary/extended/logical). And I can also add something to dump the disk layout with all its partition, sort of replacement for sfdisk. But I first want to work on the partition creation support using libparted.

tuipveus
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Joined: Thu May 14, 2009 7:02 pm

Post by tuipveus » Mon May 18, 2009 2:00 pm

fdupoux wrote:... But I first want to work on the partition creation support using libparted.
I don't know about libparted, but I tried to specify exact position with parted and it was not possible in megabytes, percents or sectors. Parted always left small gap between partitions. With cfdisk and fdisk I didn't have same problem.

I liked the idea about giving bunch of commands to parted with one line, but still old fdisk was working better and had all options I needed. Ofcourse, parted has much more options, like resizing whole filesystem.

Now I have script which will backup and restore disk/image from either network or usb-stick. It is easy to use, user just press 1 to backup and 2 to restore. Filename is given according mac-address of PC. At first script tries to mount network-share from predefined location, if it is not able to, it will look files from usb-stick.

Before it restores images, it will check with smartctl that target is correct device. Last partition of the three is built from all space left in device and after everything has been restored grub is installed.

It works.

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