...
>I have got the same message:
>File size for /vol1/vol1.dsm must be less than 68,589,453,312 bytes
...

Your postings on this problem did not include your Unix Resource Limit
values for the process involved in the operation, which may be your
artificial limiter.  Those working in a Unix enviroment have to become
familiar with this subject area: it's a continual gotcha.
See:  http://www-1.ibm.com/support/docview.wss?uid=swg21083765

  Richard Sims