Symantec backup exec 2010 R3 backup updating catalogs takes a long time

We run Symantec backup exec 2010 to backup file server, windows 2008 Domain controller, Microsoft SQL 2008 servers, now there is a issue, the backup exec stuck at updating catalogs for a long time, the speed is 32mb/sec, only 22GB backed up, please tell me how this can be resolved, thank you.