While migrating a ReiserFS partition to XFS, I noticed that df reported a
pretty significant space utilization difference between the two
filesystems. I transferred my files using two methods, and both had
First I used tar from /xfs: "tar -cl /reiserfs | tar xv", then I used cp:
"cp -a /reiserfs /xfs". Here is the output when I ran "df -h" after each
file transfer operation:
Filesystem Size Used Avail Use% Mounted on
/dev/hda5 2.0G 692M 1.4G 33% /reiserfs
/dev/hda3 952M 746M 206M 78% /xfs
If this is accurate (although it doesn't seem accurate as I will later
elaborate), then XFS uses 52MB more than ReiserFS does for a relatively
small partition (this is actually my root partition, and I only exclude a
small boot and the home partition).
I decided to check using du by running "du -csm" and found that ReiserFS
uses 734MB and XFS uses 733MB. This looks more accurate. Would anyone know
what's wrong with df? It's a much handier tool to use than du, but if it's
not accurate then it doesn't look like a good tool to use, handy or not.
Thanks in advance for your comments and suggestions.
Linux, MS-DOS, and Windows NT ...
... also known as the Good, the Bad, and the Ugly