Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch (Debian [LWN.net]

Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch (Debian

Posted Apr 26, 2006 15:21 UTC (Wed) by Duncan (guest, #6647)
In reply to: Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch (Debian by apolinsky
Parent article: Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch (Debian Administration)

> [C]an anyone suggest a way of converting a reiser
> partition to ext3, short of a copy from one file
> system to another?

While it's theoretically possible, it's also theoretically extremely
difficult to do in a "safe" manner. Reiserfs' dynamic inode allocation
and tail writing makes a working implementation extremely difficult, as
an "in place" conversion implies there's known unallocated free space in
which to start writing the converted data, and reiserfs breaks enough
traditional rules in that regard that one would virtually have to be a
Namesys employee familiar not only with the reiserfs code, but with the
years of practical experience and knowledge of what /doesn't/ work, that
they've gathered.

It's not something that just anyone could do and get it right, IOW.
Basically, the most practical way to get such a thing would be to contract
with Namesys to create such a converter. I'm sure they'd be very happy to
develop such a converter application, given a commercial contract to do
so.

Of course, that would cost real money, likely a non-trivial amount of it.
Practically speaking, it's easier, cheaper, faster, and more reliable, to
just buy another hard drive if necessary, and go the copy route.

Duncan

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Filesystems (ext3, reiser, xfs, jfs) comparison on Debian Etch (Debian

Posted Apr 26, 2006 17:22 UTC (Wed) by remijnj (subscriber, #5838) [Link]

Basically, the most practical way to get such a thing would be to contract with Namesys to create such a converter. I'm sure they'd be very happy to develop such a converter application, given a commercial contract to do so.

I'm not so sure they would be happy about this because they would be creating a tool so people can move away from reiserfs to ext3. Wouldn't that freak them out. Then again, money can buy lots of things.

But i agree that buying a disk is easier/better.

But maybe there is a way to do this, if both filesystems have a resize tool which can make partitions bigger and smaller you could do the following:

resize the reiser partition to just fit the data
create a new ext3 partition after it.
copy enough files to fill the ext3 partition
resize the reiser partition (smaller)
resize the ext3 partition (bigger)
goto 3

And when all is done you remove the reiser partition.

This is probably not possible with the existing tools because you would also have to move the ext3 partition forward on the disk to make this work. But i don't know the state of these tools nowadays.