migrating volumes -- Recipes? Critiques?

[Joel Rees]

I'm finding my /var partition kind of tight, so I thought I'd ease the
crush and (avoid fragmentation) by making a new partition for just
/var/cache and moving all the stuff in /var/cache over.

(Yeah, this is all under LVM, so I could just make the /var partition
bigger, but my home and /usr partitions are already splintered a bit
as it is.)

So I made the new partition and used

tar --acls --atime-preserve --numeric-owner --selinux --xattrs -cf
cacheball /var/cache

and, in /mnt, with the new partition mounted there,

tar --acls --atime-preserve --numeric-owner --selinux --xattrs
--preserve-permissions --preserve-order xf cacheball /var/cache

checked the results, and re-booted. X11 doesn't want to come up, just
sits there with the pointer in the middle of the screen.

Possibly relevant stuff from /var/log/messages:

-------------------------------------
ay  5 13:25:42 fed gnome-session[2561]: WARNING: Client
'/org/gnome/SessionManager/Client1' failed to reply before timeout
May  5 13:25:42 fed smartd[2414]: smartd received signal 15: Terminated
May  5 13:25:42 fed smartd[2414]: smartd is exiting (exit status 0)
May  5 13:25:42 fed gnome-session[2561]: WARNING: Unable to find
desktop file 'at-spi-registryd-wrapper.desktop': 検索ディレクトリには妥
当なキー・ファイルがありませんでした
May  5 13:25:42 fed gnome-session[2561]: WARNING: Unable to find
desktop file 'gnome-at-spi-registryd-wrapper.desktop.desktop': 検索ディ
レクトリには妥当なキー・ファイルがありませんでした
-------------------------------------

Any thoughts?

I'm probably going to go ahead and drop the new partition and just
expand /var, but I suspect this has to do with selinux, which I've
been avoiding learning how to do right.

Joel Rees