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We had a LVM of almost 16TB with ReiserFS. We now want to add more disks, but we cannot continue using ReiserFS, as it has a maximum capacity of 16TB. This volume is being used to make incremental backups with RSync, which hardlinks unchanged files.

We know that we can use rsync or fsarchiver to accomplish it, but both of them are very slow and consume huge amounts of memory, as it has to remember the inodes of every file.

We used dd and ssh to copy the partition to a temporary place and now we want to change the partition type to ext4 64bits (or another type if someone knows a better solution).

emi
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1 Answers1

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If you want to change the file system type, you're going to have to use a tool like rsync or tar or fsarchiver. The main thing though that I would think is for you to consider the possibility of finding a different backup system than using rsync and using hard links.

The problem is that hard links and using duplicate directories for incremental backups is a very inefficient data structure for storing backup information. This is one of the reasons why using rsync to copy all of these backups is slow and painful. It also means that using fsck to perform a consistency check is going to take a lot of memory in order to make sure the link count for all of the files will take a large amount of memory --- for the same reason that rsync, tar, fsarchiver, etc., will require a large amount of memory.

So my recommendation is to look at a backup system such as bacula, which uses a proper database to store the catalog of backed up files, instead of trying to use directories to store that information. And to use this as an opportunity to transition to a much more scalable backup solution.

Theodore Ts'o
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