DeviceImage Tools

[Bastian]

Hello,
1. is it possible for zsplit to be on the same harddisk that´s data is saved.
Example:
In your documentation first example you boot from hdb and save disk hda on hdb while zsplit is installed on hdb too. I am interested in a slightly different case: Assume you boot linux from hda and you want to save hda on hdb. Any problems?
2. Is zsplit better than a simple dd command (dd if=/dev/hda of=/backuphda/hda.img bs=16K)? What is the advantage of zsplit in comparison to dd if I do not care about splitting the image?
Thank you
Bastian

[jurij]

Hi Bastian,
The main problem during backups in the constellation which is proposed by you is the open files. If files which are to be saved are opened and read/write operations are running, you cannot be sure that you can avoid following scenarios:

1. Files can be accessed by two or more processes at the same time, and the backup procedure can be broken.
2. File which is changing its content just in the moment of saving is not consistent, and after the restore operation will have the other content as before saving.

Therefore it is a good idea to do the, so called, cold backup. You should start your backup software from another partition or device as that which should be saved. Also it is important not to forget that the saving partition (or partitions on device) should not be mounted. It is the best way to prevent the possible existence of opened files and running read/write operations. Only in this case you can be absolutely sure that your backup is consistent and restorable.

By the way, I have tested the constellation proposed by you. It works. But I cannot say for sure that it will work in all cases and circumstances.

The overview about the advantage/disadvantage of zsplit comparing to dd you can read here:
[url]http://www.device-image.de/forum/phpBB2/viewtopic.php?t=8[/url]

Regards,
Jurij