OpsCenter lost history after rebuilt

we are trying to generate some client count and backup capacity historic reports. But we found all history got lost before the time we rebuilt the master. The master rebuild was caused by a diaster, we recovered full catalog and database. Is there any way we can fix it?

NBU master: HP-UX 11.31 IA64, 7.1.0.4

OpsCenter: 7.5.0.6 on windows 2008 R2, with OpCenter Analytics licensed.

thanks in advance