Import VM vreeze / can't import template by Xenserver console and CLI

Import from VM hangs for hours: xe vm-import filename=xx.xva
Not able to create disk on the exising SR from the XenCenter console. Only by cli possible.

Dell Engineer allready confirmd that there is no hardware failure.
Dell servers are fully patched.
Xenserver 6.5 sp1 is also fully patched.