[Bug-tar] Restore time for a heavily hardlinked tar archive ?

[DCI Roaming]

Hello

My servers are running Debian Sarge, Tar is version 1.14.

I wanted to transfter data for one of my servers to another.
This server is doing on disk backup using Dirvish, i.e. it's doing a
copy of the files the first day and then it's hardlinking the files that
are not modified. I have 115 backups stored on the disk.
The data is about 180 GB and the on disk backup is about 220 GB, the
data is not changing too much. There is about 600 000 files of "real
data", and about 600 000 files with 100 hardlinks on each of backup.

I made one archive for the data and one for the backup, sending them to
the other server through SSH using :
tar cvf - /srv/data/ | gzip -c -1 | ssh address@hidden cat ">" /srv/data.gz
and then restoring using :
tar xzf /srv/data.gz

The data archive was done in 5 hours, and restored in about 4 hours.
Don't remember the archive size, something around 110 GB I think.
Everythink seems normal for this one.
The on disk backup archive was done in 15 hours and is 140 GB, which
seems ok. But the restore is running for 3 days now, and it has restored
less than one third of the archive.

I have an impression that restoring a hardlink is taking as long as
restoring the full file, so the restore of the on disk backup will be
100 times longer than the restore of the data.
How long should be the "normal time" to restore such a heavily
hardlinked archive ?