Does Netapp have any numbers that they could share publically on how often they see filesystem failures in the field (i.e., double disk failure, spare drive bug, etc.) that would require restoring all the data from tape? I did a quick count in my head and figured we have roughly 21 filer-years of operation (1 filer running for 3 years, 2 for 2.5 years, etc.) without a catastrophic failure yet. Is the actual observed number more like 50 filer-years? 100? 200?