I have a single controller that suddly all the aggr0 disks failed and now can boot to maintgance mode, and I can see that the aggr1 which contains my data is still online. can I install new disk and reinstall without wipping aggr1, we don't have a vaild support contract with Netapp so we can't get support from them, any help will be much appreciated.
You can mark aggr1 as root in maintenance mode (aggr options aggr1 root); it will create empty volume AUTOROOT and mark it as root. You will need to reconfigure filer from scratch though (including entering all licenses), or restore content of root volume from backup.
It is rare that all disks fail at once, so it may give you chance to troubleshoot and recover your root aggregate though.