Also, Brad and I have been saying lockup, but this is not the traditional system suddenly freezes and nothing happens.
The system is clearly up, and many things work. But any process that accesses a file in zfs (probably, in such a way that needs to allocate memory or put something into ARC, or ?) blocks. Often the wchan is zio. Often it is flt_noram5. These processes remain stuck even though there is free ram.
