After upgrading from 5.5 to 5.6, the disk on the server seems to freeze every time I try to make a backup, using flexbackup to a Samba share on a local PC. Everyting seems to work fine, but after 5-10 minutes the server locks up, with the "disk activity" LED constantly on. It doesn't seem related to specific files; and the problem also occurs if I use tar from the command prompt. There are no errors in /var/log/messages. The total backup should be something like 1 GB, so I don't expect I have the often mentioned ">2 GB" problem.
Any suggestions?