I recently .tar'd a Windows partition, then compressed it in 7-zip .7z format splitting at about 4gb.

.7z is a container format (like .zip) that does not need an extra container for multiple files/spanned archives.

In one way, .tar.7z is redundant, because .7z does not need .tar to create these archives, but that is what I did because .tar has a reported history of effective backup & because I needed to split the archive & compression process into two steps.

What I don't know:

Is .7z or .zip good for Windows partition backups?

Windows hidden & system files/folders are correctly archived by default?

Restorations functional?

There's a 7-zip forum on SourceForge (https://sourceforge.net/p/sevenzip/discussion/) but I do not have an account there yet, here more.

Similar question elsewhere:
https://forums.whirlpool.net.au/archive/1827562
7zip Entire Windows Partition

I assume you did that from a Running Linux system.

I know nothing about Windows links and hidden files or file attributes. But it is tar(1) that would have would be concerned about file attributes, not 7zip.

If you did "tar pcf" maybe it would work. But I think dd(1) would be a better option, then compress and split it.

1 members found this post helpful.

7z is compression software, not backup software.
Tar is archive software, not backup software.
Either or both can be used as part of a process for backing up data, but they are not optimal for partition backups.
There is software made for backups that might serve better, but if you are creating a backup in one OS of data on a file system designed for a different OS backup software may not understand the data involved properly.
Your BEST option is imaging software, designed to image a partition or an entire device. Certainly dd can be used for that, it is a primary purpose of that software. There are other partition backup tools that are specific to this situation that should work as well or better.

Have you considered backing up the Linux stuff in Linux, and the Windows stuff in Windows, instead of trying to cross the two?

2 members found this post helpful.

Windows apparently used to have a cumbersome tool called "Microsoft Backup." (Which never had the simple grace and elegant utility of Apple's "Time Machine.") Nevertheless, I would now seek out a "true backup utility," running in the Windows native environment.

Because: "the true test of a 'backup utility' is when everything has just crashed and you are now actually tasked with restoring from it."

If you use both tar and 7zip better to name it .tar.7z. Otherwise you can give it any extension, like .t7z or .qdfsfd too. Irrelevant.

if you compress a tar file with 7zip it is completely irrelevant. a tar file is just a file and not a partition an you can use whatever compression tool you like on it. Nobody knows which compression tool will give you better result, it depends on the content.
file attributes like system/hidden files are just attributes, in general tar does not care about those attributes. But if you want to manage a windows partition (ntfs) properly you need to use a tool which can manage these attributes too.
I still think tar cannot manage all the ntfs attributes properly, but probably I missed something.'
if it is important to you, register.

Similar question elsewhere:
https://forums.whirlpool.net.au/archive/1827562
7zip Entire Windows Partition[/QUOTE]

And as it was already recommended several times use windows and windows based tools to backup/restore windows.

Not sure how alone I am on this, but I am motivated by fear.

A restoration process might not be available or the archive itself might not restore properly.

So I use multiple formats, usually content with builtin Windows Image, AOMEI Backupper .adi, & dd.

Thoroughness

Linux can be tricky with file permissions but does not have Windows version of hidden & system attributes, so I do not worry about it much.

I have been adding tarballs to the repertoire, but based on this feedback I might rethink my options.

Why tarballs? dd wants the whole partition despite usage (vs. free space) & that is a bane.

You can zero empty space, and if you do then the dd image can be compressed with any compression tool effectively.

There used to be a command line switch in zip to preserve extended attributes. No sure if that's a thing anymore.

And that may not preserve MICROSOFT file system attributes, it understands the LINUX file system extended attributes.

this is just the duplicate of https://www.linuxquestions.org/quest...ce-4175736356/
it was already discussed. I don't really understand why do we need two (or more) threads about something which is completely pointless.
Discussing tar, 7z and similar tools to backup and restore windows partitions (and ntfs) is just wrong. If you want to have a reliable backup/restore solution us what is recommended for the given OS, do not even try to create a new solution. You will fail, and you will only realize it when you have no chance to recover.