ReiserFS and Partimage

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ReiserFS and Partimage

Post by frindly » Fri Dec 05, 2008 11:55 am

the following text i found on wikipedia, can somebody explain it correctly to me? Is it a bad idea to backup a reiserfs partiton to another reiserfs partiton, or is there no problem, because i use the compression of partiamge...???
Nevertheless it is recommended[by whom?] not to store ReiserFS v3 images on a ReiserFS v3 partition (e.g. backups or disk images for emulators) without transforming them (e.g., by compressing or encrypting) in order to avoid misleading the filesystem. Reformatting an existing ReiserFS v3 partition can also leave behind data that could confuse the rebuild operation and make files from the old system reappear. This also allows malicious users to intentionally store files that will confuse the rebuilder. As the metadata is always in a consistent state after a file system check, corruption here means that contents of files are merged in unexpected ways with the contained file system's metadata. The ReiserFS successor, Reiser4, fixes this problem.

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Post by admin » Fri Dec 05, 2008 1:34 pm

I know that Theodore Ts'o (aka tytso) who is an important ext3/ext4 developer said that sort of things about reiserfs. Basically when the disk has bad blocks, it's searching for data structures that looks like reiserfs data structures, so if you have a file containing something like internal reiserfs data structures, the fsck program will think it's data structure for the real filesystem.

Anyway it's safe to save a compressed partimage or an fsarchiver image on a reiserfs partition, since compressed partimage data won't look like the original reiserfs data structures. And fsarchiver is only focused on the file contents and attributes, not on the filesystem data structures, so there is no risk.

Anyway, reiserfs is the best filesystem for speed and saving space in filesystems with a lot of small files. But the default ext3 filesystem is the best choice for critical data and servers with many processors / cores, since it scales better, because ext3 does not use the big kernel lock which reiserfs is using.

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